M57 slide question

[.50cal packer]

After receiving my Yugo, I gave it and the mags an overnight bath in mineral spirits to remove the cosmoline. Took it out and scrubbed the heck out of it, oiled it again, and reassembled it. It looked great. Things seemed to function well after I lubed it. The slide catch would release with ease with or without a mag present. Two days later, Today, with the mags unloaded, I wanted to play with my Pistol a bit. So I inserted a mag, and tried to release it. It wouldn't budge . I removed the mag, and it released fine. I inserted another mag, had to pull the slide back and forth while pushing down on the release to get it to go. Now I can release the slide with mags in while doing that. But with the mags out, it will close just fine. What am I missing here??? Why wont the mag indicator work without problems? Also, how do I fix this problem? Any and all advice is welcome and thanks in advance.

[Tidewater_Kid]

My experience with the Yugo cosmoline is that it wicked sticky stuff. I had to use a heat gun to get the last of it out of mine. I think the mineral spirits soften it up and then it re-hardened after a few days. If you don't have a heat gun try boiling the parts.

TK

[carguychris]

If you don't have a heat gun try boiling the parts.

+1. Although I don't have a Yugo, in my experience, boiling water is by far the most reliable and cleanest method of removing cosmo.

It's best to do this outdoors. Get a campstove or turkey fryer, and an old or cheap stock pot you won't use for anything else. Fill with water, bring it to a nice rolling boil, and dunk the parts in it. For a pistol slide, I suggest hooking it to a piece of coat hanger wire so you can move it around and get boiling water into all the nooks and crannies. For small parts, I simply drop them in the water, then drain everything through an old kitchen strainer. After 30sec or so, you should see drops of viscous yellow or orange fluid floating on top of the water- that's the cosmo. You'll obviously have to re-oil the parts afterwards.

[.50cal packer]

Thanks for the boiling water idea. It does make sense. I'm aware that cosmoline doesn't like heat, and boiling water would certainly do the job. I was unaware of the different types of cosmo though. You mentioned, the Yugo version is super sticky. Where as my Russian variety of cosmo, on the MN, practically melted away. Very little scrubbing was involved with the bolt and barrel when soaked in just the mineral spirits. I'll give the water a try, and see if it was the first thing I should have done. Thanks for the advice guys.