Maybe it’s the screen in the bottom of the bowl that heats up.
Could be (some sort of metals toxicity), or it could be any of the countless adulterants (intentional or otherwise) which could be present, from other drugs to agricultural chemicals.
12 posted on 12/26/2012 3:53:28 AM PST by Smokin' Joe
(How often God must weep at humans' folly. Stand fast. God knows what He is doing)