Feed in distilled water to the dishwasher, should be fine then
Was going to suggest a decent camera cleaning kit for the sensitive parts, and maybe a few tins of compressed air on hand to blow dust out of tight places.
Be careful not to blow dust into the Spark internals if blowing out cooling flow through areas . . . you might be best to remove covers to do this so you can blow it out well. Depends on your a self help level of confidence if you want to go this far.
There are usually drone maintenance services by many drone shops, which might be a good thing to do once you hit a fairly high # of flying hours, not sure, maybe 100hrs ?
I bet they get pretty dusty inside, my computers get very dusty after a short time, and that's inside the home !