resin smells...bad. i say clean it as often as u want to. at least once a month, every 2 weeks is good too. get some rubbing alcohol(the more % of alcohol, the better), pour it into a bowl or w/e(something u can throw away if u needed to) then let ur pipe soak in that shit for a while. rinse off with water....lots of water...and some mild soap. wait for it to dry, take a whif, if it smells like alcohol, clean it some more. after it drys take ur lighter and light ur pipe like ut taking a hit(but with no weed) and move ur lighter around the bowl and suck(so it burns off any extra alcohol around your bowl!)

its the fastest way i kno but there is prolly special stuff u can soak ur pipe in that'll take off all the resin and u dont have to rinse off with water afterward.