Can Bristol Finish be applied over other finishes?
Yes. As long as the other finish is intact, in good condition and fully cured according to the manufactures instructions. The only exceptions to this are applying over waxes and oil base finishes.
What is the best way to remove Bristol Finish?
A heat gun and scraper are the most efficient way to remove Bristol Finish, remember to use a scraper that will not gouge the wood. Chemical stripper works as well but you have to deal with the toxic byproduct that comes with using it.