Poly goes over shellac if it's dewaxed. It's impossible to keep people
at a party from placing drinks on a table, at some point.

Try removing the ring with a tiny bit of alcohol on a rag wiped around
and around the ring. Don't saturate the cloth and don't let the cloth
sit in one spot. The idea is to create a fast dissipating "vapor trail"
of alcohol, barely more than fumes.

Dave

SonomaProducts.com wrote:

Education might be in order but, kids and fine furniture are never a
great mix.

I'll bet you never thought you'd be one of those uptight people running
around putting coasters under everyones drink.