I removed a waterproof camping bag in my student appartment today that's been filled with stuff to find that it has left a moldy spot on the untreated plywood it stood on. It's been parked up right next the door/window.

I guess the damage has already been done since I think the white stuff may be mold, but is there anything I can do to minimise any further harm?

(It's darker than it looks in the picture)

bag mark

2 Answers 2


A dilute solution of bleach sprayed on it will kill and neutralize the mold. Then wire brush the damaged spot. If you want to prevent this later, seal the plywood with something, primer or polyurethane.

(While bleach contains chlorine which is not good for you, the chlorine is volatile and quickly evaporates. It is typically used by brewers to sterilize equipment for this reason.)


Put hydrogen peroxide on it, let it sit for a bit and scrub it. Repeat if needed.

Bleach works well on solid surfaces like cinder block, but not porous like wood.

Or, could you replace the piece of wood?

  • Bleach is actually more harmful than most of the molds. You can also just use soapy hot water. Damp the mold / area to keep the dust down. Then scrape it and get rid of the mold. Then for the leftover use hydrogen peroxide. A small amount should be good. Make sure the area is well ventilated to the outside. You should also seal off the room so the mold does not go to other areas. May 27, 2014 at 23:54
  • Cinder block is porous.
    – iLikeDirt
    Jul 22, 2015 at 15:50

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