What am i doing wrong when i get crumbs out of mac keyboard?

if one key still feels gritty after the air, a cotton bud with a little isopropyl alcohol run round the edge of it, mac still off. squeezed out, not dripping.

nothing needs turning on, if anything the opposite. shut the mac down (or unplug the keyboard if it's a separate one) so you're not typing gibberish into something while you clean. then hold it at an angle, roughly 75 degrees so it's nearly upright, and go along the rows with compressed air in short bursts, left to right. turn it on its side and do it again from the other direction. most people only do one pass flat on the desk and wonder why nothing comes out. don't flip it over and bang it, and don't try to pry keys off on a four year old laptop keyboard. those clips snap really easily.