Just about any detail shop can clean your car. Detailing is much more thorough and safer (and more expensive) than going through a drive-through car wash, but doing these on some sort of schedule is an excellent way to keep your Tesla shiny and looking like new. Most of these references (again, all based on member feedback on Facebook, with no implied recommendation from the club) will come to you.
On the Spot Mobile Detailing has gotten good member recommendations. They have locations in Annapolis Junction and Frederick.
Reda’s Mobile Detailing is based in Westminster.
Jay Monty has gotten good member feedback, as has DR Details DMV.
Best Care Mobile Detailing is another option.
Xact Detail, Enhance Auto Care, and HP Mobile Detailing have come up in the past as well.
Cliff Dewey’s Auto Detailing, which also offers a member discount, is located by the White Oak MVA (near routes 29 and 650). They do not come to you, however.