My mother gave me my dad's Ruger MK I 22 pistol after he started showing signs of senior dementia. I don't think that it had been cleaned in 40 years (he bought it in the 50's). I shot a few rounds through it and it won't function properly 1 out of 5 rounds. I think a deep cleaning would remedy this. I've taken it apart and want to immerse it in something to get all the grime out. I'm open to suggestions. Oh, and by the way I have a Mk 1 also so I know how to put it back together, at least I think I do.

You`ll probably hear a few suggestions but, I`d soak in Kerosene.

I learned the hard way that GUNK will dissolve powder crud GREAT, but it will also "cut" blue. BEWARE!

Any of the aerosols will "blow out" as it floats the crud. Carb cleaner. Brake cleaner. Etc.

Me? I would use kerosene in a spray bottle and compressed air. Remove grips, plastic, I think. Have to find mine to look. Spray with kerosene. Hit with compressed air. Repeat. Then WD 40 until you can clean the barrel for lead as needed and add some better lube/preservative. I use Breakfree. Triflow. Etc. Leave to drip and dry. Replace grips.

Much as I liked Monkey Wards and Federal .22's especially for the price, they seemed to leave a lot more crud. Winchester a lot less. You have to work with what you have to see what works for you. luck.