I've had it in my home as well. The exterminator almost freaked out when he saw it in the upper corners of the walls where the meet the ceilings and around the windows. I figured he'd report me to some agency about health hazards, so I dealt with it.

What I did was get a few towels, a bottle of the clorox bleach spray (for kitchen use) and sprayed the stuff, then wiped it away. It came off easily and didn't return.

The A/C guy will have something he can spray and wipe inside the central unit as well, and would be a good idea.