Hi bearhntr, if you asking about cleaning a system pipe (with a reservoir), using a sheet of tissue paper, twist to a point and screw as much as you can into the shank and keep twisting, when exhausted, remove and it will be covered in gunk, repeat until clean, you can dip the tissue in a little alcohol for extra clean. You should also run a pipe cleaner through the air hole within the shank. If your Petes are P-Lip you might find that thinner pipe cleaners work better, Falcon pipe cleaners are great if you can get them in the USA (I’m UK) You might want to take a look at the International Peterson Pipe Club site, ton’s of information on Petersons and we are good bunch, not in competition with this site.
Happy Puffing, Ken.