I've bought a lot of old used marlin 60's. Great guns. I've found that in most cases the light strikes are simply caused by fouling in the pin channel and the ejector pockets. Just take the bolt out, blast everything clean with brake cleaner (I like it because it's very inexpensive and evaporates completely... gas and some powder solvents are "hard", they leave behind a residue), then lightly lube the bolt.
Evoc is dead on about the fouling getting impacted on older guns, if that's the case, a bent safety pin works just as well and is a hell of a lot cheaper than dental tools. If it's INSANELY filthy you can just soak it in brake cleaner overnight (use a container with a lid, that stuff evaporates fast) and that gunk will slide right off.
I'm continually amazed at how dirty some of those older 60's are. I know somewhere in the manual it says you never need to clean the barrel, I'm starting to think that many 60 owners don't believe you need to clean the things at all.