how to get some oil in

Without looking at it I'd guess WD40 through a tube on the can might free it, but puff pack graphite powder into the mechanism is probably the best if there's enough access. Any help?

WD-40 is _not_ a lubricant, it dissolves lubricants and leaves a gummy film. Unless getting it stuck further is your goal, do yourself a favor and avoid using a Water Displacing agent as a lubricant.

I stand corrected. Does work well for freeing rust/gunk sometimes though & I thought pp graphite might sitll work on top. Thinking more about limited access than ideals I suppose. Regards

Yeah I use WD-40 to flush out old dried up lubricants and get something moving, then apply new lube. The WD-40 will also help flow the new stuff into tight places.