I picked up a pair of Steiner 8x56 bino's at the thrift store that were mistreated. The objective bells have been unscrewed and there is dirt and debris inside that need cleaned out. One of the bells had been screwed back on crooked but doesn't seem worse for wear. A small flap  of the rubber armor seems to need glued back down.

There looks to have been an adhesive or mild threadlocker on the objective threads. Would this need replaced? They seem pretty secure.

How best to clean these without causing more problems? They seem like awesome glass and once cleaned up would look like new. So far I've used ziess eyeglass wipes on the outside surfaces to remove fingerprints.

Or should I just send them to the factory?

Thanks.

Optical/lens cleaners that are intended for anti-reflection coated lenses, and a microfiber cleaning cloth.

If the residue on the threads goes all the way around it might have been a sealant of some kind, for air and gas tight sealing.  Unless there's an O ring or some other kind of seal.

It would be best to not seal in humid air when you close them back up, or you'll get fogging/condensation inside the unit.  Of course it's probably pretty dry in Nevada, so maybe just wait for the lowest humidity day you can.

I had no clue about either. Thanks. Yes, Humidity is normally very low but we're having a very wet June. I'll proceed accordingly.