Shit, this sucks, a lot. The VIC-20 35k/SD2IEC boards have arrived, and I decided to test fit one of the PCBs. It's stuck in there, won't come out no matter what I do.
WD40 attacks plastics. Best is to use a contact cleaner degreaser. It'll have the same lubricating properties without degrading plastics. And on vintage stuff you don't want to do even the slightest harm.