I have always been curious how to clean a mobo from stuff like TIM that gets washed off with my paper towel. It is on the PCB and around some components that I am in no hurry to touch.. Contact cleaner then?
Yep! Contact cleaner spray for electronics. It's safe and gets the job done, usually able to dilute and clean the nooks and crannies where not even cotton swabs will reach. The downside is that it generates some humidity so you have to ensure that the board is dry before you power it back on. Use it generously and you can make it board feel new.
Just make sure it's pure contact cleaner and not a variant that contains lubricant mixed in. Those have their uses, mostly where there is some mechanical stress involved, but they leave residue over time and can potentially make their own mess.
I use rubbing alcohol and blue paper towels and que tips..
Isopropyl at 99% plus a flannel or similar soft cloth that doesn't carry static is a good thing to clean large components but you can't use these to say, clean out some thermal paste that may somehow found its way to the LGA socket or in between tiny SMD components. Contact cleaner can.
Wouldn't recommend ethanol unless you have access to high purity ethanol, which tends to be controlled access in many regions as it's highly combustible and can be distilled into bootleg alcohol