I use a small tub filled with hot water and a little liquid dishsoap to clean my progaurd 7. I soak the filter for a few minutes and then agitate it in the water. It doesn't ever come out looking new, but after 2 or 3 batches of hot soapy water, the crud is gone. I use a little compressed air to blow backwards through it to get most of the water out... but I'm carefull not to get the air nozzle too close the the filter. I don't want to make holes in it, I just want it to dry in less than a week. Once it's 100% dry, I lightly re-oil it. I have a drop in paper filter that I run while the AFE is being cleaned.
As a side note:
I've had the PSM setup with the Progaurd 7 for over a year. A few months ago, I started commuting to work in my truck. When that happened, I bought a paper filter to run daily. I save the AFE for towing or hot-rodding. I can tell a difference in EGTs, but only at higher boost levels. Daily driving is not affected by the paper filter. Also, the cost of a paper filter is about the same as an AFE recharge kit so the $$ really isn't much different. For me, the main advantage is that I don't have to clean the AFE very often... which I hate doing.