When you take off the collection cup simply wipe off the inside with paper towels. Just be sure to get all of the gunk off of it. Also make sure while you have the cup off to wipe off the neck that is on the main body. If it has crud on it, it won't skim as well. I personally clean the neck almost everyday, and dump the cup about every 2-3 days. About every 2-3 months you should clean the entire skimmer. Completely remove it from the aquarium. Disconnect the intake and clean the inside of it with a cleaning brush. Take off the pump and clean the impeller and the inside of the moter by simply taking out the impeller. This is also a good time to replace the 2 airline tubes which will be getting dirty at this point. Use the same brush to clean down inside of the main body. Rinse it out well. Finally, take a VERY small amount of vaseline and coat all of the o-rings on the skimmer. This keeps them from drying out and becoming faulty. Don't worry these o rings should not come in contact with water and it won't hurt your aquarium. Put everything back together and put it back on the aquarium. Set the top of the froth line at 1/4 inch from the top of the neck and wait. After this type of cleaning it takes a little while for it to start working again. By the end of the day it should be going strong again. Sorry it took me so long to get back to you. Have a good one.
