Wet spots are the result of several things; the fact that glass and wax expand and contract in very different amounts and that there are temperature fluctuations. Heating the glass before pouting (a pin I think) is the best method for avoiding wet spots. In theory, heating the glass causes it to expand, you pour in the wax into the expanded jar, and then cool. AS the wax cools it will shrink but the glass is also shrinking, so not wet spots. Well, nice theory but it ultimately depends on how much your wax will shrink and the cooler the temps, the more it will shrink. Air conditioning can be a cause, drafts while cooling. Transporting candles during the winder or a outside display, will all cause more wet spots. A lot of us don't worry about them any more, most customers don't seem to care.