I turn down the bubbles, remove the cup and lid and take it to the sink
wash in warm water and nothing else except a sponge
rinse thoroughly and set back up onto the skimmer
adjust the bubbles back up and thats it. if you have microbubbles they
supply the black foam piece to go on the end of the output. (i dont use
it because i have no microbubbles) if you use some additives or epoxy
in your tank you will have microbubbles until you wc it out.

The plastic that the skimmers are made of usually have a coating on them that eventually wears off and is not harmful, the vinegar wash gets rid of it faster and speeds up the skimmers break in time. This doesn't have to be done often just at start up and then occasionally after that. I personally find that a clean collection cup works much better than a slimy one as the bubbles can grab onto the plastic when clean. My Aqua C Remora would stop skimming altogether after a couple of days until the cup was cleaned again. All my HOB skimmers stopped producing micro bubbles within a 4 week period and after a complete tear down and cleaning. If you find it skimming too aggressively just raise the cup up a bit until you are happy with the results.