I’ve been using a small plywood surface that I’ve carried around with me which is the same idea but i was just kinda sketchy with sand and snow!
A landing pad or your palm is a much better option than "dusting off" from the ground.
Just think of all the particles blasted about at start up...waiting for GPS home point...and then lift off.
The debris could be circulating through the Spark via the on board cooling system and the motors themselves.
Fly Safe
