RCA Caps

Is anyone using RCA caps (plugs) on their unused audio connectors?

I'm considering going with either Telos or Cardas.

I like the idea of keeping dust out of these while benefitting from EFI/RFI rejection.
I have been using the Cardas for years. I wish I could afford them for the S-Video and all my XLR ins/outs that are unused, but as you have seen they are not cheap. For the SE caps there is a brans out there that has a little knob on them, if you can I would get those as the Cardas caps can be a pain to get off on SE jacks that are close.
I purchased the generic RCA Caps from Parts Express. I can't tell the difference between them or the Cardas ones visually. I've put them on varying pieces of equipment in my mostly mid-fi solid state systems and I haven't heard a difference either way with them in place. I've put them on preamps, CD players, integrateds even on a subwoofer amp and I could hear no difference. I agree with Theo to look at the caps with the little knobs on them. The generic caps I have can be hard to remove if your RCA jacks are in a tight space.
I bought a set of 10 pair of caps from Vintage Audio Lab off of eBay for about $20 shipped. Not really sure I can tell a difference, but better safe than sorry. Especially since it was only $20.
I bought 80 caps off eBay and they are pretty good for the price of 20 for $15 bucks.
I definitely noted a better screen on my Plasma TV with covering all the RCAs on the back. The background had less grain. So for the TV, they really are worth the money. For the stereo, i would say it too had a very slightly 'blacker' (quieter) background.
For the price of the Cardas, it is a little steep, but for some generic type, they are worth the bother, on stereo equipment, somewhat.
IMO, for unused rca INPUT jacks shorting plugs are preferable to caps, although of course in many cases I would not expect either one to make any difference.

Caps will do nothing to reduce coupling of internally generated rfi/emi onto the unused input lines, from where it might couple into the signal path that is in use. The same goes for rfi/emi that may originate externally, but which enters the component via a pathway that bypasses the rca jack and then couples onto those unused input lines. Shorting plugs can help in either of those situations.

Shorting plugs should not be used on output jacks, of course.

-- Al
Excellent response as always Almarg, I was going to mention the same thing. I also, have not experienced a difference when using the RCA caps. I need to mention that I have never had a problem with EMI/RFI either and therefore YMMV.
I am gonna buy some clear plastic jobbys, anyone that does vintage knows that the jacks are closer together and with the plastic jobbys I can cut the edge off to fit. I just wanna keep the dust ( dead skin ) off.
I have tried RCA plugs off and on over the years, but I could never hear a difference.
A well-designed selector switch of a preamp will short all inputs except the one selected. With the old style rotary selector switch this requires an additional "deck". No doubt this deck has been eliminated to reduce cost.