Computer and electronics safe to use:
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My guess though is any thing that was loose or can be loosened (cable connection somewhere?) can be, would be the only thing to watch out for. Less on Mac Pro than on my PCs with fans and clips for power or an SATA cable that could slide off.
I don't know what mac model you have but DIMMs do have a tendency like any electronic part to attract and hold onto dust.
The old G5s were notorious for how much dust could build up down inside those systems and get empacked. And somehow still work but not as well.
If you see temperature sensors that don't look normal, or the fans seem to be working when you aren't doing anything, that would then be a reason to take action. Otherwise, not sure if more harm than needed good.