We are in the process of building/replacing our kitchen cabinets because of an accident where an 8' wall cabinet fell and destroyed 40+ years of various cooking glassware. Luckily my wife and I were not cut nor hurt when this happened. We were trying to hold it up as we unloaded it before it came completely down. Didn't work. Anyway, we wanted to build eventually anyways, and this gave us the opportunity do so. We chose to do a completely wood, ply for the carcasses and poplar for the face-frames and cope and stick doors. The build was uneventful until I put on the finish. I was careful to check for glue residue before staining, and found a few spots with MS. Used a cabinet scraper and sanding to eliminate those spots. Unfortunately, there were white spots that showed up after applying the stain that I cannot figure out what they are. Stain will not adhere just as if it was glue, but it isn't glue. It is in spots where there was no glue applied. It seems to be somewhat of a bleach I suppose. Nothing I do will cover it. I have never seen this before. I suspect it may be some type of chemical that may have been spilled on the wood, although MS and naptha do not show any signs of it when applied over it. Any suggestions on what this may be?
Sorry for the winded post, but this has me puzzled.