Not (full disclosure) a direct answer regarding a bonafide safe vac.
What I do is just go outside and use canned air (following instructions) to loosen and blow out dust and debris.
If going outside is not possible then I set up a vacuum cleaner in close proximity to the open case. Then I turn on the vacuum, check the air flows between case and vac. Then use canned air to blow out the dust.
Just adjust vacuum nozzle and/or case position as necessary to ensure that the dust is pulled into the vacuum. Take your time - no need to rush.
Move case and nozzle as necessary to target an area to be cleaned.
Do not go too powerful with the vacuum. Dust is light and will go with the air into the vacuum. Too much "vacuum" and/or...