I spilled oil based polyurethane varnish on my white carpet. I tried as best as I could, to remove the varnish with paint thinner. Although I thought most of the stain was gone, I've noticed that the spot has now begun to turn yellow and is very unsightly.
Do you know of any solutions to my problem? I've tried many of the off-the-shelf cleaning products, but they have not proved to be effective.