Find a small bottle at a hobby/craft store that seals up tight, and of course, fits the stem. Then buy it. Take 'er home and slap your stem in it, then fill it up to about 3/4 of an inch from the top with as high a percent of iso alcohol that you can find ( I use 91%). Screw or attach lid, and then shake it and let it sit awhile (depending on how clogged it is). Then shake it again. Remove stem from bottle with tweezers to save the alcohol (don't wanna dump that out). Rinse your stem in warm water (dries quicker because it heats the stem). Let it dry. Then let the good times roll. Later, make some hash oil outta that used iso alcohol. Then let the good times roll some more. -S.L.
PS- If you have a PD, then lwien's method is the best way.