Help, my valve cap hot melted on, i cant put air in them !

OK, so my next project EG have in line has somewhat low air in the tires, so i go to unscrew the valve cap { AFTERMARKET} and it wont turn, i took big wrench to it, and STILL wont turn, so pretty much i can't unscrew the tire valve cap, its another junk aftermarket part , and it look's as if it just melted inside it self to the valve, so what are my options ? should i just wait the month till i get new tires or have u had this problem and have a solution ? if so what ? thanks 
