Clean, inspect and re-seal in Cosmolean.
Cosmolean will prevent rust or any kind and is much easier to clean.
If all you can get is 100% you need to dilute with naphtha to a 70 - 30 mix
70% naphtha and 30% cosmolean.
I have used this for years on gun, engines, etc...
Great stuff for storing metal.
I say shoot it. Pick up some surplus while it's still cheap-ish and have fun. Mosin Nagants are all about fun IMO, very reliable and accurate enough. Mine is my most successful hunting rifle. It's just a stock configuration 91/30, but it works great.
Thinks for all the input Cleaned, is there a trick to get the 5 round clips to work The clips have circle with a triangle in it. Rifle scope is in the mail. Need to set up targets and safety block behind it have used 2, 1 inch ply wood nailed to 1X6 filled with 6 inches of sand for my old 50 cal in the past
Are you talking about the top loading stripper clips? There should be an obvious place near the back that they insert into... press down on the rounds (not the clip itself) and they should feed into the mag... remove clip, bolt forward and you're ready to go.
With some clips you do have to do some tweeking... but I'm sure you can handle it.
Put the clip into the notch, push down on the ammo near the center of the top round. It might go in hard and in fits and starts. Be careful not to cut yourself on the clip! It's easy to do. They should go in all at once when you finally get them moving. You're pushing past a spring.