I'm getting my original 4 into 1 exhaust cerecoated as close to chrome as possible. The pipes are off and at the plater, and I intended to replace the exhaust gaskets in all cylinders in the process of re-assembly. I note a slight ridge about 1/32 of an inch in from the rim of the exhaust. I don't think it is the used exhaust gaskets, but could be wrong. Are these crush washers, or do they retain a round shape once installed? These are more or less flat. If they are indeed crush washers, what is the best way to remove them? Thanks to any responders.