If you’ve been staring at your floors wondering “how do I clean my tile grout lines properly?” you’re not alone. Dirty grout lines are one of the most common — and frustrating — cleaning problems in homes, especially in kitchens, bathrooms, hallways, and older houses.
Many people assume dark grout means it was installed that way. In reality, most grout starts out white or light grey and slowly turns darker as it absorbs grease, dirt, and residue over time.
I discovered this firsthand when I cleaned my parents’ house. They genuinely thought their grout was black — until I cleaned one section and revealed bright white grout underneath. That experience led me to this heavy-duty grout cleaning method, which I now use whenever I need to clean tile grout lines properly.
Why Tile Grout Lines Get So Dirty
Before you can clean tile grout lines effectively, it helps to understand why they get dirty in the first place.
Grout is porous. That means it absorbs:
- Grease from cooking
- Foot traffic dirt
- Body oils
- Cleaning product residue
- Moisture and dust
Over time, this builds up layer by layer, causing grout lines to look grey, brown, or even black. Simply mopping the floor or wiping tiles won’t remove this grime — it sits inside the grout.
The Mistake Most People Make When Cleaning Grout Lines
The biggest mistake people make when trying to clean tile grout lines is adding water too early.
When water is added to a degreaser, it turns the product into soap. Soap spreads grease instead of lifting it and pushes residue deeper into the grout.
That’s why so many DIY grout cleaning attempts fail — the grime never actually leaves the grout.
The Best Way to Clean Tile Grout Lines Using a Heavy-Duty Degreaser
This method focuses on removing what’s actually making grout dirty: oil-based grime.
What You’ll Need
- A heavy-duty degreaser (workshop strength works best)
- Paper towels or old towels
- A grout brush or stiff toothbrush
- A bucket of clean water
- Gloves
This is a simple method, but technique matters more than products.
Step-by-Step: How to Clean My Tile Grout Lines Properly
Step 1: Always Test First
Before cleaning tile grout lines, test your degreaser in a small, hidden area. Grout types vary, especially in older homes.
Step 2: Do Not Add Water
Start with completely dry grout lines. Do not pre-wet the tiles or grout.
Water at this stage will stop the degreaser from working properly.
Step 3: Apply Degreaser Directly to the Grout
Apply the heavy-duty degreaser directly onto the grout lines, working in small sections only.
The goal is to let the product sit on the grime, not run across the tiles.
Step 4: Let It Sit for 5 Minutes
Allow the degreaser to sit for about five minutes. This gives it time to break down grease and dirt trapped inside the grout.
You may see the grout change colour slightly as the grime loosens.
Step 5: Scrub Lightly With a Grout Brush
Use a grout brush or toothbrush to gently scrub the grout lines. You don’t need heavy pressure — the degreaser does most of the work.
Step 6: Wipe It Up Before Adding Water
This step is critical.
Use paper towel or old towels to wipe up the degreaser and loosened grime before introducing water. This removes the dirt instead of spreading it around.
Step 7: Rinse With Clean Water
Once the product and grime are wiped away, clean the area with fresh water to remove any remaining residue.
Step 8: Change Your Cleaning Water Regularly
Your rinse water will become soapy quickly. Change it often.
The purpose of this step is to remove product residue — not to clean the grout again.
How to Clean Bathroom Tile Grout Lines
Bathroom grout often contains soap scum, body oils, and moisture buildup. This degreaser method works especially well in showers and around bathtubs, where grout absorbs oily residue from personal care products.
For mould-prone areas, you can repeat the process or follow up with a separate mould-specific treatment once the grout is clean.
How to Clean Kitchen Tile Grout Lines
Kitchen grout lines collect grease faster than any other area of the house. This is where a heavy-duty degreaser truly shines.
Apply the degreaser carefully along grout lines near stoves, sinks, and walkways, and always work in small sections to avoid drying.
How Often Should You Clean Tile Grout Lines?
For most homes:
- Deep clean grout lines once or twice a year
- Spot clean high-traffic areas as needed
- Wipe spills promptly to prevent absorption
Once grease buildup is removed, grout stays cleaner much longer.
Why This Method Works on Old and “Black” Grout
In many older homes, grout looks permanently dark because it has absorbed decades of grime. This method removes the coating that causes discoloration rather than bleaching the surface.
That’s why it worked so well on my parents’ house — what looked like black grout was actually white grout buried under layers of dirt.
Safety Tips When Cleaning Tile Grout Lines
- Always test products first
- Wear gloves when using degreasers
- Ventilate the room properly
- Avoid mixing cleaning products
- Never scrub aggressively enough to damage grout
The Bottom Line
If you’ve been asking “how do I clean my tile grout lines so they actually look clean?”, this heavy-duty degreaser method is one of the most effective solutions — especially for older, heavily soiled grout.
By avoiding water at the start, wiping up grime before rinsing, and changing your cleaning water regularly, you can restore grout lines that look permanently dirty.
Clean grout changes the entire look of a room — and once you see the difference, you’ll never go back to basic mopping alone.
Frequently Asked Questions About Cleaning Tile Grout Lines
How do I clean my tile grout lines without damaging them?
The safest way to clean tile grout lines is to avoid harsh acids and abrasive scrubbing. Using a heavy-duty degreaser applied directly to dry grout, allowing it to sit briefly, then wiping it up before rinsing removes grime without weakening the grout structure. Always test in a small area first.
What is the best cleaner for dirty tile grout lines?
For heavily soiled grout, especially in kitchens and high-traffic areas, a heavy-duty degreaser is one of the most effective options. Grout discoloration is often caused by grease and oils, which degreasers are designed to break down. This makes them more effective than vinegar or bleach for deep cleaning.
Why shouldn’t I add water when cleaning grout first?
Adding water too early turns degreaser into soap. Soap spreads grease instead of lifting it and can push grime deeper into porous grout. Starting with dry grout allows the degreaser to work properly, breaking down dirt before it’s wiped away.
How long should I let grout cleaner sit?
Letting a degreaser sit on grout for about five minutes is ideal. This gives it time to break down grease and residue without drying out or damaging the grout.
Do I need to scrub tile grout lines?
Light scrubbing with a grout brush or toothbrush helps lift loosened dirt, but heavy scrubbing isn’t necessary. The cleaner should do most of the work. Over-scrubbing can damage grout over time.
Why does my grout still look dirty after mopping?
Mopping cleans tile surfaces but doesn’t remove dirt trapped inside grout. Grout is porous, so grease and grime build up over time and require targeted cleaning to remove.
How often should tile grout lines be deep cleaned?
Most homes only need a deep grout clean once or twice a year. Kitchens, bathrooms, and high-traffic areas may need more frequent spot cleaning.
Can this method be used on bathroom tile grout lines?
Yes. This method works well on bathroom grout, especially where soap scum and body oils build up. For mould issues, clean the grout first, then treat mould separately if needed.
Why does grout turn black over time?
Grout often turns dark because it absorbs grease, dirt, and cleaning residue over many years. What looks like black grout is often originally white or light grey grout covered in buildup.
Should I seal grout after cleaning?
Sealing grout after it has fully dried can help prevent future staining and make regular cleaning easier. This is especially useful in kitchens and bathrooms.
Is it safe to clean old grout lines?
Yes, as long as you avoid harsh acids and always test products first. Older grout can be more porous, so gentle but effective methods like degreasing and wiping are ideal.
Why does my rinse water turn soapy?
Degreasers emulsify oils, which causes rinse water to become soapy quickly. This is normal. Changing your cleaning water regularly prevents residue from being redeposited onto the grout.
* This article was originally published here
