Speaker binding posts with plastic covers

I have similar situation and all I did is just busted plastic covers leaving metal screw caps. They don't hold up tight and within the time they will twist off.

Later I've replaced them with brass nuts

@curiousjim Deoxit F5 is specifically designed for switches and has lubricant. Any other Deoxit is also similar to penetrating oil 

Don't use solder on speaker wire, for the same reason you don't use it on 200A electrical connections.  It makes the wire brittle and is low conductivity. Always crimp.

Most people won't agree, but I would probably just replace the binding posts.  I make my own binding posts but they are low mass and very similar to these from KLEI.

@czarivey 

Hmm,  I must have misread something.  Back to google.

Thanks.

@rfprice 

Again, assuming they are like the speaker posts on the A21+ I owned, they were the best speaker terminals I have used.  Without having to yank them vice tight like on other speakers posts on a handful of amps I have owned, they held my speaker spades with an iron grip.  Part of the plastic holds the spades so they will not rotate.  Once you see how the spade needs to fit into the terminal, you are good to go.