I'm a big fan of /r/whatisthisthing For the easy stuff that I might know it's always long-since identified by the time I look at it. The hard stuff is usually

I'm a big fan of /r/whatisthisthing For the easy stuff that I might know it's always long-since identified by the time I look at it. The hard stuff is usually either some corroded lump of metal from a magnet fisher that could be anything, or something truly obscure. Plus it's fairly often enlivened by the answer "It's live ordnance, put it down and call the authorities, no don't try and unscrew that bit, it's the fuse!"