I have a cheapo swing arm from an AMX Full Suspension bike. I'm using it for my longtail build in the utility forum.

I've gotten the lockring off the BB, but am having trouble getting the cup out. The wrench flats look like they have been rounded off, as I can't fit a 15mm wrench on them, but a 16mm seems to large.

I've got the SOaB soaking in PB Blaster right now, but is there any tips for removing stubborn, crappy, cups with wrench flats?