Vacuum is a good start, if you stuff a rag in the vacuum intakewith a smaller tube and then tape it up you can create a very small vacuum nozzle.
If you can actually see the dust, get a long stick like a pencil and wrap double stick tape around the end and you can pick up a lot with the tape.
The last option is to use compressed air with a long nozzle, it will blow most of the debris back out the top opening (watch your eyes).
That sort of dust and clean up dust will not cause any real problem if some of it gets in the engine, it will pass right through, but you should try to get as much as possible of it out before you start the engine.
Large solid objects like nuts bolts and screws down the intake absolutely must be physically removed but small dust like that is generally harmless.