This might be a dumb question, but:
I need to replace the sealing washers under some tank cap vent screws. Like what's on the 3 gallon OMC tanks. These are prevented from coming all the way out by a thin stainless steel washer with spring tabs on it, that engage a groove near the end of the screw. I don't see an obvious way to remove the washers without buggering them up. Is there a trick to this? What are these washers properly called and are they a hardware store item?