Do connection/contact solutions work or not?

the right ones like pro gold work, they keep the sound from degrading not improving it.
Larry

I like kontak. It does improve the sound-sometimes its not so subtle. If you have tubes, apply it to the pins and sockets. (With the power off!)

Works with all signal and speaker cables.

I would agree with Larry. The purpose is to remove and/or prevent oxidation. If the contact is already clean, it doesn't "improve" sound; rather it prevents it from deteriorating. If the contact is dirty, it "improves" the contact in the sense that it restores it to a clean state.

Thanks for the good answers. Preventative maintenance is always good.

The BIG THING is to not use too much!
Whatever kind is used apply only enough to coat the surfaces. Usually wipe off any that will come off with a dry paper towel (Viva towels do not scratch)
The coating only needs (and should be) a few microns thick!
Too much is what degrades the sound after awhile. (a really big problem with too much Tweek)