Laynerb, try isopropyl alcohol first, it's a decent solvent that shouldn't affect the scrimshaw, although I'd try it on a small spot to be sure. You can put it in a can and brush it on liberally with a soft paint brush which won't scratch. it'll evaporate quickly and won't leave a residue. If you polish the bolsters with anything try to keep the compound off the delrin. It'll likely get quite dark through polishing and will be absorbed to a slight degree by the plastic. Needless to say it's VERY difficult to get out once this happens.
Eric