I would leave the lid off at least until the temp drops to around 150°F or so. Unless you boiled for 90+ minutes, there is still some DMS being released. Minimal perhaps, but above 140°F, anything that creeps into the wort is killed anyway. So you are fine uncovered while the temps are high.
"I brew with a water cooler and some part from the toilet." - JohnnyO
"I do gravity feed the last gallon or two through my Therminator, but I expect you could suck start a Volkswagen before you could suck start one of these. - GilaMinumBeer
"..... Bull was right." - TXCurtis