I am replacing spider valve in year old Praher multiport valve. I have done this 3 or 4 times in the past, but I am having very S-l-o-w progress this time. The gasket is really glued in there! I don't know what kind of glue Praher used, but every millimeter of the gasket is glued! Is there a solvent that would make this go faster? I have already spent a couple of hours and the gasket is only 1/3 of the way removed. I don't want to scratch the seat and ruin the valve!