Removing a stain from Polyurethane
Does anyone have any ideas on how to remove a stain from a polyurethane finish. I thought I'd ask before doing it the hard way. I don't have ready access to the problem (its 5 hours away) - but if the solution is risk-free enough, I could have my son attempt it before making arrangements to return the shelf.
My current ideas are try Mineral Spirits or maybe even diluted bleach but I don't know the reaction of either by the poly. (Based on my workbench, I'm thinking mineral spirits will be non-effective)
The finish is 3 coats of high gloss (oil-based) polyurethane over a natural "color" stain on a birds-eye maple bookcase shelf. I am kind of surprised that it stained, I thought the poly was fairly impervious, but apparently a wax candle of some sort was set on the shelf for a short period and some component of it leached into the poly finish leaving a round wine colored mark. I'm not sure if the stain penetrated all the way to the wood (I'm hoping not). The poly has been curing at least 6 months.