I've always been sceptical (afraid) of pulling petcocks, seems they sometimes weep afterwards. I've always pulled the tank flushed with good gas or mineral spirits, poring out through the fill hole. Flush the petcoch in reverse, tank upside down on a bench, repeat rinse. Use a can of computer/camera air to blow petcock. I've use carb cleaner, but only on tanks to be repainted. You get the idea, it's like back flushing a swimming pool filter.

Last edited by MACMC; 07/18/2013 1:17 PM.
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. H. L. Mencken