There are all sorts of carb cleaners out there but the one I find works the best on old gunky oil and grease, like in the photos of the springs, is Easy Off Oven Cleaner, BBQ Grille formula.

Once that gunk is cleaned out it will be easier for any oil to get into the smaller parts and help to free them up.

I have used this stuff on a lot of alloy parts and it has never damaged anything yet.