Cardas Caps Worthwhile?

I use small rounds of kitchen tin foil on the back of my Musical Fidelity amp (which fall off if you fuss around too much), for dust and air grunge protection. I wouldn't mind having the Cardas Caps instead, but am too cheap.

Bmpnyc: Yes, I live in the LA area. We keep an open place (no air conditioning) and the air gunk covers everything (even dishes in closed cupboards). I never thought of putting anything on the unused inputs/outputs until I heard of the Caps. I cannot even see the back of any of my components, but feel better knowing that sticky air stuff is not coating the unused connections (it just makes sense, no matter what you use). Clean contacts are a must for good sound. I cannot believe the improvement in sound when I clean the pins on signal tubes (I have had noisy tubes become silent again, just from this).

I just use electrician's alcohol and cotton swabs if the pins are in good condition (also clean the globe with the alcohol). If the the pins are not in good shape I lightly use very fine emery cloth (think that's the name of it) and then follow up with the alcohol. Be very carefull if the pins are gold plated. I would like to try out the Kontak, but still have not purchased it. I just had my amp cleaned and spec'd, but will need to get some brushes (or maybe pipe cleaners?) for the tube sockets as I change tubes quite often.