So, after spending many hours, heat stripping, then liquid stripping, then steel wooling and sanding the 100+ year old fur/pine built in cabinet doors in my home, I seal the now bare wood, and apply the Minwax oil stain, only to be horrified at how poorly the stain took. The old finish was the original faux grain, with a redo on top of it that was probably done 40 years ago. There appears to be some sort of wood filler residue in much of the grain that jumped out when I applied the stain. Any thoughts on what this putty like stuff is, and how I can get it all out of the wood so the stain will go on evenly?