How To Remove Old Silicone Caulk

Now that the mold problem under the sink has been fixed, it’s time to replace the sink so we can return to a normal life with modern plumbing in the kitchen.
The steps for installing a new sink or replacing an existing sink are the same except if replacing a sink, any old silicone caulk or plumber’s putty that is stuck to the countertops and the sink from a previous installation will have to be removed and cleaned up. If you haven’t done it already, read our post on how to remove a sink first before following the next steps.

Steps to Install or Replace a Drop in Kitchen Sink

  1. Remove and Clean off old silicone caulk or sealant from countertop and sink (this post)
  2. Attach the faucet to the sink (this step can be done later, but is easier if done before the sink is installed)
  3. Install sink in the hole on countertop
  4. Putty and attach drain assemblies
  5. Attach the garbage disposal
  6. Attach drain lines to the drains
  7. Attach the water supply to the faucet

How to Remove Caulk or Sealant from Countertop and Sink

So, what is the easiest way to clean silicone caulk from countertops and sinks? The sink will not sit flat and level if old caulking is left on the countertop or underneath the lip of the sink, so it has to be removed. The caulking also has to be removed from the top of the sink where the faucet was attached.

silicone caulk remover gel

Low-odor, no residue Silicone Caulk Remover

I don’t remember exactly what type of caulk was used last time, but it was a clear, flexible caulking that was probably a Silicon caulk/sealant or a mixed Latex, Acrylic and Silicon blend. Either way, it is stuck very well to the sink and countertop and is difficult to remove.

There are some specially made removers like “Silicone-Be-Gone” to remove silicon caulking, but since I was not exactly sure which type I used last time, I didn’t want to spend time and money buying a product that may not work. I tried using some paint thinner (mineral spirits) on a small spot and it seemed like it was starting to work, but the paint thinner was drying so fast, it really didn’t have much chance to work. I read that the area could be covered with plastic wrap to prevent the paint thinner from evaporating, but I decided to try scraping the caulk off with the putty knife and avoid all the fumes.

Example of how to remove silicone caulk with a silicone remover product.

Removing Silicone Caulk with a Putty Knife or Scraper

It took me about an hour to scrape the caulking from the underside of the sink lip and the countertop using the putty knife. Neither of the areas that I scraped would show after the sink was set back in place, so I didn’t worry if the the job was not perfect.

how to remove old silicone caulk with scraper

Using putty knife to carefully scrape old caulk from countertop.

I had to be careful not to peel up the laminate countertop, so I was always careful to scrape away in the direction that would make sure I did not catch the edge (Figure 1).

I also had to be careful on the upper part of the sink where the faucet was attached with caulk to the sink. I was able to removed most of the caulking with the putty knife there as well, but also used a nylon scratch pad when I was concerned about damaging the sink.

The putty knife worked well enough for me. I did not try using a razor blade scraper which may work better on very hard surfaces, but I was concerned the razor blade could gouge the laminate countertop if I made any mistakes.

If this were a larger job, I would probably used a fan to ventilate the house and used paint thinner and plastic wrap to keep it from evaporating too quickly.

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