Motorcycle clutch corks

[Isambard]

Back last century, when recorking clutch plates was the norm, to trim the corks, accepted practice was to use an engine exhaust valve that was refaced to a fine edge as the tool in the lathe...
As most used wedge shaped Ferodo inserts originally, the corks, procured from the local pharmacist, were boiled up, to soften, then pushed sideways into the recesses, allowed to cool, then trimmed. Pharmacist corks were preferred over those from the ironmonger, as they were very high quality, no flaws.