Shoutout to the guy who told me to use a dab of synthetic oil on a sticky shutter curtain
I tried it on a Nikon FM2 last Tuesday and the oil migrated onto the film plane, ruining three rolls of a client's vacation shots, so now I'm looking for a better fix for that specific problem.
Man that's a real bummer, sorry to hear it messed up your client's photos. Using oil on shutter curtains is such a classic piece of bad advice that keeps getting passed around. For the FM2, a tiny bit of lighter fluid on a q-tip worked for me once, but you gotta be super careful. Maybe try that on a test roll first next time.