Those things are usually overbuilt, so risk of damage per firing is usually low. I am not making a claim that it is safe to shoot--I haven't looked at it personally. However, if it doesn't clean up well it just won't be as accurate as it should be.
Clenzoil will cost you about $14 for a bottle and I believe Sweets is about $17. It might be more or less depending where you buy. Yeah, you can try Hoppes, etc but I can tell you NOTHING will be it clean like the combo I mentioned unless you tank it. A gun smith would probably charge about $35 for a simple clean and since it's corroded already, add money to that figure. Not trying to discourage you, just trying to help you decide how far you want to go. Sometimes projects can be fun and a good learning experience.