Use your wet or dry vacuum outside on the end of the drain line to suck out the lent and trash . I do this about once a year. A window unit don't count, only the central unit needs this help...
Just let the window unit fall out the window and it will be clear after you set it back in..Second thought, I keep my shop unit tilting down outside to take care of the extra water build up so no worry there...The big unit inside does make a mess if not cleared regularly...