Silver Mica Caps on Phono Inputs

Hi there, I am curious if anyone has used silver mica caps for bypassing RF noise on a phono input and what their experiences are?  I'd like to use them to squash RF coming in from the phono cartridge to the preamp, so they are shunting the input lines.   

I could use polypropylene or polystyrene but the RF characteristics of a wrapped cap is not very good for shunting RF noise to ground.