Items Needed:

  • 3% Hydrogen Peroxide (enough for 2-3 soakings)
  • Cotton rags
  • Palm Sander and/or sand paper
  • Matching stain for hardwood floors and a brush to work the new stain into the wood

Total Cost: Approximately $20

Total Time: Approximately 2-3 days

Recently my girlfriend told me her cats left a bit of a mess under their litter box–a little pee stain that had blackened the hardwood floor under the plastic/rubber mat protecting the floor from the litter box. It was probably the new kitten which she’s had since December. Unsure how long the stain had sat there before she noticed, she tried Googling some things to try to remove the stain herself, and settled on baking soda and vinegar–which did not work–so here’s a How-To of how I removed the stain from the hardwood floors.

A side note, this is repair tip is for real hard wood floors and not any of the cheap floating wood or parquet floors (I’ve never tried this on that kind of flooring).

She estimated the stain had been there a few weeks, and the floor was recently refinished approximately 1 year ago. The size of the stain was about 20 inches long, and 4-6 inches wide (take a look at the photo, basically the outline of mat used under the litter box). The weather condition in Milwaukee, WI currently is hot & slightly humid, so if that helps works into your calculation for your own repair, maybe that will help (ie. if it’s really dry, you might be able to do a 3-4 treatments in a day).

When I got into town, I immediately went to work on the stain. I Googled that hydrogen peroxide and some cotton rags would work to lift the stain and slowly bleach the wood under the finish. I picked up the 3% Hydrogen Peroxide at a drug store (Tip: it’s in the First Aid isle, and not the Cleaning isle as I originally thought). I also grabbed some cheap $2 cotton t-shirts to use as rags–which didn’t work well, and I ended up doing another trip to Home Depot later for actual cotton rags.

Step 1: Bleach the Stain

Dowse the area with the stain with the 3% hydrogen peroxide and then lay the rag over the stain. The rag should be slightly damp to the touch and not 100% drenched in hydrogen peroxide. Leave it to dry.

Step 2: Repeat As Necessary

I wiped the area down with some damp hydrogen peroxide again to see how clean the stain lifted. I repeated the steps again until I was sure the stains had lifted as much as possible (2 more times and the took until the next day).

Step 3: Sand

After I noticed the stain had significantly lightened, I used my palm sander to lightly sand the top layer of the stain. I’m not sure what grit I used, I think 60-100. It was pretty rough, but then I used an 800 grit to, black sandpaper to remove the rough edges. It shouldn’t take that many passes. The stain was still visible, and what’s happening is you’re basically removing the pet stain, original wood stain, and finish in this step.

Step 4: Repeat Bleaching As Necessary

I used the 3% hydrogen peroxide method again — this may or may not be necessary, but because the stain had been there over 2 weeks, I figured we needed to do another lifting and bleaching to really make sure we get that stain out of there. Some spots were already light enough, but when dowsed with the hydrogen peroxide again, appeared to reveal the stain again.

Step 5: Sand and Smooth

Clean the area, again with a damp hydrogen peroxide solution. The stain should be almost gone by now, and just take that palm sander to it to really clean it up, finishing with the high grit sand paper.

Step 6: Stain Wood with Matching Stain

I stained it with the wood stain I picked up at Home Depot. It was a little can and approximately $8. I also picked up a brush since I didn’t have a staining brush, but I’m sure you could also use cotton rags or something else you’ve got laying around if it’s a small area.

Check out the before and after photos, and let me know if you have questions or suggestions in the comments for other users.