I've been seriously half-assing my computer cleaning for a long time, but my mom got me a gag gift of a MICRO VACUUM ATTACHMENT KIT, and the set was like a swiss army knife of getting up in that machine.
The only downside was I had to rig up a longer philips head screwdriver with drill bit attachments to get the intake assembly out. It's two larger fans screwed in with two hex guys.
Also needed the magnet wand to get the hex guys back in.
The kit consists of an adapter that screws on to the vacuum, a 36 inch bit of flexible tubing, and a series of other parts. I used the oval brush, round brush, and crevice tool.
It's this kit:
https://www.ebay.com/itm/284772843431Mom paid a dollar.
I had previously duct taped a drinking straw to a shop vac and crushed the sucky end to fit into crevices.
This kit was far more effective than my jury rigging. Also taxed the motor a lot less.
The one down side of this kit is that I can't get the tubing off the adapter, so I wasn't able to shove it back in it's box, but it fit in my toolbox just fine.