where to get shorting plugs?

I did as Jgiacalo described. Chopped the cable off leaving about 1/2", stripped the insulation and twisted the wires together. I didn't bother covering them with tape, I just twisted the exposed wires into a little pigtail real tight to the cap. You can do the same for non-shorting plugs, but in that case it is important that the wires are NOT shorted, and that they be covered so they don't short.

(http://www.cardas.com/content.php?area=oem&content_id=7&pagestring=RFI/EMI+Protection+Caps) read the following and pay attention to what is said about shorting outputs:(http://www.siteswithstyle.com/VoltSecond/Shorting_plug_rca/shorting_plug.html)

Thanks all, very helpful. I learned that Dedicated Audio sells the Cardas ones (Cardas produces both caps and shorting plugs).

seandtaylor99  +1  His suggestion works great for me. Noticeably cleans up some HF hash. For the 6 unused inputs on my preamp, instead of making stand-alone shorting plugs, I made 3 pair sets. In other words, I connected/shorted the bare wire from two RCA plugs together - and installed each pair in their respective left and right channels. I didn’t solder - just twisted the wires together and taped them. I was pleasantly surprised how easily I could hear the improvement. Defiinitely, DO NOT use shorting plugs for outputs!  YMMV

Check these out. $18 for 10 pieces including shipping from HK. Well made, looks great and works great.