This is what some locks will look like after sitting on the gun for a few decades without the occasional strip and clean. The locks should be completely disassembled, cleaned and lubed. Just pulling the locks off, a few squirts of oil and scrub won’t make them function correctly and efficiently.

[Linked Image from i.ibb.co]

[Linked Image from i.ibb.co]

What they should look like after being properly cleaned, polished and lubed:

[Linked Image from i.ibb.co]

[Linked Image from i.ibb.co]

[Linked Image from i.ibb.co]