CLR is a go-to cleaner for tough stains, rust, and hard water buildup, but it’s not safe for everything.

Its powerful formula can eat away at certain materials, leaving behind damage that’s expensive—or impossible—to fix. The last thing you want is to ruin your countertops, floors, or appliances just trying to clean them.

So before you reach for that bottle, check out this list of things you should not use CLR on!

#1 Natural Stones

If you’ve got natural stone tiles and countertops (like granite, marble, or slate) - CLR is a big no-no.

These types of stones look gorgeous but they’re also pretty sensitive. Natural stone is porous, which means it absorbs stuff like water, oils, and cleaners.

CLR can seep into the stone and leave behind permanent stains or dull spots.

You’ll definitely want to avoid any acid-based cleaner (and CLR is definitely one of those) on your stone surfaces.

If you want to keep them looking shiny and fresh, go with a gentle, pH-balanced cleaner made specifically for natural stone. These will keep things clean without damaging the surface, and trust me, that’s a lot less headache than trying to fix damage from CLR.

#2 Painted Or Coated Surfaces

Another big mistake is using CLR on painted or coated surfaces.

If you’ve got painted walls, cabinets, or even furniture, using CLR on these surfaces could strip away the paint or cause the coating to peel off.

It could leave your surfaces looking scratched or dull, and that’s definitely not what you want.

Also, some coatings like varnish or polyurethane are meant to protect surfaces, but CLR can break down these protective layers. This applies to both indoor and outdoor surfaces, like your patio furniture, so keep CLR far away from these areas.

If you need to clean a painted or coated surface, use a mild, non-abrasive cleaner and a soft cloth to wipe things down. This will clean up the grime without the risk of removing that pretty paint job or protective coating you worked so hard on.

#3 Brass, Copper, Aluminum, Or Galvanized Metal

Metal surfaces like brass, copper, aluminum, or galvanized metal can be easily damaged by CLR.

While CLR is awesome at removing rust, it’s actually way too aggressive on these metals. It can cause them to tarnish, discolor, or even corrode. That’s the last thing you want if you’ve spent time setting up a shiny brass faucet or copper fixture.

Brass and copper are particularly prone to damage, as CLR can strip away their natural patina, leaving them looking dull or even discolored.

For these metals, you’re better off using a cleaner made for metals or a homemade solution of vinegar and water, which is gentler and won’t cause as much damage.

#4 Wood

Wood is one of those materials that you definitely don’t want to clean with CLR.

Whether it’s your wooden floor, a dining table, or wooden cabinets, CLR can be way too harsh. The acid can strip away any finish on the wood and leave it looking dull or even damaged.

Plus, if it seeps into the wood, it can cause discoloration or weaken the fibers.

For wooden surfaces, stick with something gentle. A mild soap and water solution will usually do the trick, or there are cleaners made specifically for wood.

Trust me, you’ll save yourself a lot of stress by keeping CLR away from your wood.

#5 Colored Or Older Bathtubs & Sinks

If you’ve got an older bathtub or sink, especially ones with colored finishes, you’ll want to avoid CLR on these too.

CLR can be too harsh for these types of surfaces, especially if the finish is worn down or aging. It can fade the color or even leave streaks and discoloration that are impossible to fix.

Instead of CLR, try using a gentle cleaner made for tubs and sinks, especially if they’re older or have a delicate finish. A little elbow grease and the right cleaner will have your bathtub looking as good as new without the risk of damage.

#6 Rubber, Plastic, Or Vinyl

Don’t use CLR on rubber, plastic, and vinyl surfaces like rubber mats, plastic shower curtains, or vinyl flooring.

If you use it on these materials, you could end up with cracked, brittle, or discolored surfaces.

CLR is way too strong for them, and it can break down the texture and flexibility that makes these materials so useful.

For rubber, plastic, or vinyl, you’re better off using a mild cleaner or even just soap and water. There are tons of specialized cleaners for these materials that won’t cause any damage, so don’t risk it with CLR. It’s just not worth it.

#7 Clothing Or Fabric

It should be obvious, but here’s a reminder: do not, under any circumstances, use CLR on your clothes or fabrics.

CLR is an acid-based cleaner, and if you get it on your clothes, it’ll leave stains that are nearly impossible to get rid of. Plus, the acid can break down the fibers in fabric, making it weak or brittle.

If you’re dealing with hard water stains or other buildups on fabric (like towels or linens), stick with a mild detergent or a specialized fabric cleaner.

For stains on clothes, a stain remover that’s safe for fabrics is the way to go.

#8 Colored Grout

Grout is one of those things that can be tricky to clean. Sure, it gets dirty, but CLR is probably not your best option.

If you use CLR on colored grout, it can cause the color to fade, or worse, wash out completely.

And once that color is gone, there’s not much you can do to bring it back. You’ll end up with a bunch of faded, dull grout lines that make your tiles look old and dingy.

If you need to clean grout, try a gentler solution, like a mix of baking soda and water. There are also specific grout cleaners on the market that won’t mess with the color.

If you really want to keep your grout lines looking fresh, stick with the gentler options.

#9 Electronics Or Appliances

Now, this one might seem like a no-brainer, but you’d be surprised how many people think CLR can be used on electronics.

You definitely should not use CLR on your phone, TV, computer, or any other electronics. It’s just way too harsh for delicate devices, and it could seep into the cracks or openings, messing up the inner components.

The same goes for appliances. Even though they might get dirty, using CLR could damage the finish or cause permanent marks.

Instead, clean electronics with a microfiber cloth and some mild soap or a cleaner designed specifically for electronics. It’ll keep your devices safe and sparkling.

#10 Pool Tile And Swimming Pools

Lastly, if you’re thinking about using CLR on your pool tile or in the pool itself—think again.

While CLR can be great for removing some mineral buildup, it’s not safe for pool surfaces. It’s highly acidic, and if you use it in your pool or on pool tiles, it could cause damage to the grout, tiles, and even the pool’s finish.

Not to mention, you really don’t want to introduce harsh chemicals into your pool water.

Instead of CLR, go for a pool cleaner. These are designed to handle the tough stains without causing damage to your pool or pool equipment.

And always read your pool’s cleaning instructions to make sure you’re using the right products.

Don’t Mix CLR With Other Cleaners!

One more thing to remember: do not mix CLR with other cleaners.

Mixing CLR with bleach or other cleaning products can cause dangerous chemical reactions that release toxic fumes. That’s a health hazard you definitely want to avoid.

So, if you’re using CLR, keep it simple and use it alone. It’ll work fine by itself without needing any help from other cleaners.

If you’re already using another product, make sure to rinse everything off before applying CLR.

Bottom Line

CLR is awesome for certain cleaning jobs, but it’s not the right choice for everything.

Some materials just don’t react well to it, and using it on the wrong surface can cause damage that’s hard or impossible to fix.

Stick with using CLR on things like shower heads, faucets, and sinks that aren’t painted or coated, and be extra careful when cleaning metals, woods, or delicate finishes.

For anything else, there’s likely a gentler product out there that’ll get the job done without the risk.

Always check the surface and the label before using CLR, and you’ll avoid a lot of cleaning headaches!

What Should You NOT Use CLR On? (Avoid These Mistakes!)