WHAT DOES PEUGEOT ADBLUE DELETE MEAN?

Considering the fact that past diagnostics / code clearing drove 3 miles and light-weight back on / motor turned off straight absent ad blue filler cap removed and tried to blow/suck by cap to check out if ventilated. Cap is not really ventilated. still left cap off and tissue in filler neck for 80 miles/no lights arrived on.AdBlue is starting to b