Plastic (polyethylene) cutting boards tend to get worn with use, eventually leading to an unsightly (and often unsanitary) surface. Between cut marks, foods, and cleaners can leave a plastic board looking pretty ragged.
But not all is lost - a quick attack with some sandpaper can refresh that cutting board, making it as good as new and saving the time and money of replacing them! This tried and true food service industry trick can help clean up even the worst of boards and prolong the life of your boards and boost the cleanliness of your kitchen.
Step 1: What you'll need
in addition to your old cutting boards
Sandpaper (ideally 25 grit through 80 grit)
metal scrubber or rough steel wool
scraper/hand plane/razor blade (not pictured)
For the sander, I'm using a Dremel contour sander. Any sander will do the job, and one with more horsepower will do the job faster. A belt sander or orbital sander would work nicely. I just didn't happen to have one handy at the moment.
Step 2: Clamp the board
Cover your work surface with a drop cloth, newspaper, etc. to catch the remnants of the sanding.
Using the clamps, securely affix the cutting board to your work surface (I usually clamp the two corners by the handle-edge (if there is a handle cut-out) since those rarely get worn from use. Be sure it's clamped snugly, as scraping and sanding can create a good bit of lateral torque on the board.
Step 3: Prep the board for sanding
Using the metal dish scrubber or extra-course steel wool, scrape the surface to remove any loose burs of plastic and begin to clean the surface. The less excess plastic that is left on top, the less the sandpaper will gum up.
Step 4: Sand the board!
Sand the surface of the board using the coarsest grit of sandpaper. Ideally, I start with 25grit and progress to finishing with 80grit. If you start too high, the sandpaper won't be successful at removing the top layer of the board.
**Be sure to use eye protection and a dust mask, as the sanding will kick up polyethylene dust which is less than pleasant to get in your system!**
And if your cutting boards are anything like mine, this is the stage when you will smell the aroma of everything you've ever cut on the board coming out as the sander gently warms the dust... this can often be a somewhat unpleasant experience!
Step 5: If sanding isn't enough...
Depending on the depth of cuts, grit of sandpaper, and strength of the sander you're using, sanding alone may not be enough. If you aren't able to sand away enough of the surface to remove cuts, gouges and slices, it may be necessary to CAREFULLY scrape the top layer of the board with a razor blade, a knife blade, or ideally - a hand plane.
Then continue sanding until grooves, scratches and gouges are removed and the surface is buttery smooth.
Step 6: Clean the surface while sanding
To help expedite the process, periodically wipe the surface with the steel wool/scrubber to remove any burs and the dust that the sander has kicked up. Unlike wood, polyethylene has a tendency to statically adhere to itself which makes the sanding process more difficult. A frequent wipe will help the process.
Step 7: Clean the edges
As the sanding process will alter the shape of the board slightly, I take a blade and scrape the edges of the board to get a nice clean bevel after I'm finished sanding.
Step 8: Clean the board
Cleaning the board should be a three-step process.
First, rinse with water in a sink to remove loose dust and particles.
Second, apply kitchen soap and rub in with your hand - NOT a sponge - to work more of the dust out. You want to avoid getting your sponge covered in loose polyethylene dust. Then rinse the board.
Third, use a sponge with dish soap to clean the board surface again. Rinse, let dry, and enjoy your like-new cutting boards.
Step 9: Enjoy your refreshed cutting surface!
Not only is the fresh surface more sanitary (deep crevices can collect and breed bacteria), but it will also help prolong the sharpness of the edge of your knives (the worn cutting surfaces can catch and dull knife edges more quickly).