Cluster Housing Refurb

Most of that is typical sunburn. The scar might have always been there since its in a spot not seen. So the needle goes all the way home. That's a good sign.
Do you find what looks like black pepper inside the can? Tap it on the table and the stuff falls out? Thats a bad sign.
If you have a Ohms meter you can get more info. Resistance post to post, ( I think this is a 20 ohm example ), if not 20 ohms, its 13 ohms. Open or infinite from post to can. Anything different is a bad sign.