I use the amazing red rag. You know it's good for everything. That's right... the amazing red rag!
You find them sold in auto stores ( i work on cars alot ). They're made of cotton, and don't easily shred or tear. If i'm wiping something, i use them. They don't cause ESD either. If i'm cleaning something that requires more attention to detail, i use toothpicks or qtips wrapped with the end of my amazing red rag. LoL.
If i'm cleaning contacts, metal (like the inside of a dusty case), or something that really requires it, i use alcohol. It evaporates easily and quickly and its safe for general use, although i wouldnt suggest it to someone who didn't know what they were doing. I really only bring out the alcohol when i really really have to.
I've cleaned out dozens of computers, cards, chips, fans, and non computer equipment, over the years. I've never used those fancy can's of compressed air, and the few times i've looked for it in a hurry at my local stores, they never have them. For me it's always been... yep you've guessed it... the amazing red rag LoL. Well that and a little creative ingenuinity!