Ditto some of mrsbooboo
1. Take out the beater bar and cut off any hairs, fibers etc.
2. Remove the filter, wash in soapy water, let air dry for 48 hours. (I actually let it air dry for a lot longer. I bought a second filter so that I could leave the wet one out until the next cleaning. I made the mistake of not letting one dry long enough and it started to smell a little funny so now I'm super cautious about putting it back in too soon.)
3. Clean the canister. (I don't fill it with water, but I do rinse it out. I'm just careful not to get water into any of the "parts". But I do rinse it.)
4. Wipe all exterior surfaces with a damp rag.