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CLR in Toilet Overnight

CLR, also known as Calcium Lime Rust is a cleaning solution that is known for eliminating the said components, especially in toilets. 

As a brand, CLR formulates that cleaning solutions are usually effective in removing stains from surfaces such as the kitchen and bathroom, upholstery, and clothing. Great! But just how does this particular solution eliminate things like Calcium and rust in your toilet? The secret lies in the ingredients and how they work.

CLR is highly acidic and it is not recommended to let CLR sit in the toilet overnight. It is important that you follow the manufacturer’s instructions carefully, and always wear protective gloves when handling strong chemicals.

How Does CLR Work?

CLR is a blend of solvents, surfactants, and other ingredients that work collaboratively to dissolve and ultimately lift away stains. As such, when you apply this cleaning solution to your toilet, it breaks down stains and dirt as well as loosens them. 

Another thing about the CLR cleaning solution is that it contains oxidizing agents that are perfect for removing stubborn stains such as those caused by rust or hard water.

That said, you should follow the manufacturer’s instructions for this cleaning solution because you may need to use different application techniques for different surfaces. Moreover, it is advisable to test the solution on a smaller area before going full in to ensure that it won’t cause discoloration or damage.

How is CLR Used for Cleaning Toilet Bowls?

A stained toilet bowl is not only an eyesore, it’s also not easy to clean. Therefore, as you anticipate the best results from CLR, you also want to keep in mind that it has to be used correctly for the best results. Here’s how to do it.

  • Get a pair of rubber gloves – Your safety comes first. As we have previously mentioned, CLR does contain some harsh chemicals that could damage your skin. This is why it is necessary to begin the process by wearing a pair of rubber gloves.
  • Turn off the water supply – You don’t want any water interfering with your cleaning or even causing water accidents. As such, you want to cut off the water supply to your toilet. Doing so will also ensure that your CLR is not washed out before it takes effect.
  • Apply the CLR – Next, you want to pour your CLR into the toilet bowl. Be generous with it and allow it to sit for a few minutes. You may notice the reaction taking place. For a maximum clean, scrub the toilet bowl with a brush and rinse with water.

You should see a shiny clean surface. At this point, you can turn back on the water supply.

How Long Should CLR Be Left to Sit in a Toilet Bowl?

The reason why CLR is such an effective toilet cleaner is that it is extremely acidic. Therefore, you do not want it sitting in your toilet bowl for too long. Typically, two minutes will suffice, but if you feel like your stains are too tough, you can let the solution sit for a few more minutes – just not more than five.

After allowing it to sit, scrub it with a brush and flush. Your toilet should look as clean as new.

Is it Advisable to Soak Your Toilet in CLR Overnight?

No. It’s not. As we have just mentioned, CLR is quite potent and should only be left to sit in your toilet bowl for a maximum of five minutes. We understand that most people would reason that the longer it is allowed to sit, the better the results.

However, that is not the case. The solution’s reaction with the stains will not take place for more than two minutes.

How Long Should I Let CLR Sit on My Shower Head?

Just like your toilet bowl, you shouldn’t let CLR sit on your showerhead for more than five minutes. The cleaning solution does not become more effective when it is allowed to sit longer on surfaces. As such, it would be best to wash it off after two minutes of sitting on your shower head.

What Can Be Used to Substitute CLR?

Perhaps, you can’t get your hands on CLR. What can you use instead? Fortunately, there are some readily available alternatives such as:


Vinegar and lemon juice are natural alternatives and they work quite well. However, do not expect them to work as fast or as well as CLR.

Lime-A-Way is a great alternative as it contains sulfamic acid to fight stains. CLR has a combination of gluconic and lactic acid.

Either way, both work well in removing hard water stains.

White Vinegar

You can use white vinegar in place of CLR if you prefer homemade cleaning solutions. The best part is that vinegar is quite effective and costs just a fraction of what other alternatives go for.

Is CLR Safe to use?

CLR contains about 12% of lactic acid. This can corrode things like Formica, plastic laminate, natural stone, carpeting, and wood, just to name a few. This is particularly true if it is left to sit on such surfaces for prolonged periods.

You should always wear gloves when handling CLR and thoroughly rinse the surface you are cleaning with cold water. Never use CLR with bleach either as you risk inhaling toxic fumes.

Ultimately, CLR is safe to use, but only if you use it as directed and keep it away from children and pets.

Can CLR Damage Aluminum?

Yes, it can. CLR is acidic and should therefore not be used on metallic or painted surfaces, terrazzo, marble, or grout, on any surface that is cracked or damaged.

As for aluminum, it is a metallic surface and because CLR is acidic, the reaction would cause corrosion. Of course, this would lead to deterioration and damage.

What’s the Difference Between CLR Pro and CLR?

Both CLR Pro and CLR are cleaning products from the same brand. However, they are formulated for different types of applications. CLR is best suited for domestic cleaning while CLR Pro was formulated with a large-scale and professional cleaning in mind.

Can you Combine CLR With Baking Soda?

No. This is not advisable. CLR contains acids which when mixed with baking soda can react to form carbon dioxide gas. This can then lead to foaming and bubbling which may turn out to be dangerous.