Just let them rot.....it will stink, but it won't hurt anything.....heck some of mine even survive the winter and will bolt come spring and flower and produce seed if you leave them alone! Depending on what the plan is for the plot come spring - just deal with it then. Like Native said you can toss small hard seed like clover into it and go that route as well. Tilling now essentially doesn't gain you anything unless your planting something that requires it right away.