Don't do it
My brother in law sells fits and stretches snooker, pool and billiard tables and when he does a 'stretch' to lengthen the time the cloth can stay on the table for playing they are very prone to ripping as well as being extremely weak on and around the pockets. Although they are tacked from underneath the slate on pieces of wood called tacking strips, wetting will make the cloth rip away leaving the tacks where they were hammered in. Around the pockets are delicate little cuts allowing for the curviture of the slate and pocket where they meet which are spray glued and not tacked.
Used to work with him on my days off.
Shaun