Glenn

You can use poly but all the shellac must be stripped off first or the poly will not stick good and will flake off. I recommend you stick with shellac since that is the original fisnish. The Water base poly will give a plastic look and will not have that amber glow of old furniture. You can use oil based poly but it will take days to dry and will collect dust will drying. Shellac will dry tack free in about 30 min or less.