Thanks for the suggestions. See this is how it would look after it was repaired and repainted. So maybe some patches of slightly different color than the paint (like not exactly matching) would help. The rust, etc would be during an actual campaign when there isn't time for the cosmetic aspects. There is grit and grime on it now (applied as a cloud mat for the diffusion channel) but maybe a bit more on the silver parts.

Those familiar with Battletech will know what I'm talking about. The above pic is a mech that is in battle but notice the metal still has a shine to it.