What if I cannot remove all the old stain?

Q: What happens if I cannot remove all the old stain from the floors? Do the floors have to be sanded to absolute perfection, or can there be slightly different shades?

This house is very old and I don’t want to stain the floor, I just want to polyurethane.

A: If a floor has been stained in the past, it is near impossible to remove every trace from the heavy, soft grain. If such trace amounts remain, it doesn’t detract from the overall look of the newly finished floor.

Related Q: I had #2716 dark walnut on my floors, but I am now trying to sand it off. A lot of the stain is down in there still. What color of stain would be able to cover over it? I don’t want to go too light, but don’t want it too dark either.

A: A professional flooring contractor, both fully trained and equipped would have no issue removing all but trace elements from the heavy grain, after which the floor could be successfully stained any colour (except a pastel colour) without any real noticeable difference.