Audio input question

[[22Hz] Productions]

	To reject RF crap in an audio input jack, approx. what value 
cap should I use to ground, and what (if anything) should I use in the 
audio path to buffer the input a little? (.01uF cap is in at the moment, 
and no cap to ground.) Will a teeny cap + pot here work alright to 
buffer/decouple it a bit and allow level control? If so, what value cap 
do you recommend? Not terribly urgent/important, just curious. =) TIA-

	Jason