This one was a bit tricky to explain in writing, but easy to see via video. To perform the maintenance, you will need at least 1/4 cup of bleach or vinegar and 1 cup of water. If your unit is in the basement with a condensate pump, you can use the same cleaning method as described. If you are in a maintenance agreement with an HVAC contractor, they should be performing this cleaning as part of your contract. Thanks for following my page for tips on how to view your home with a fresh perspective!