The compressed air cans are "aite". They tend to move the dirt a little bit and tend to only knock off dust bunnies. On some things they are completely useless. Such as 30+ year old monitor chassis. It definitely isn't gonna knock that crap off.
For general cleaning of everything: shop vac and if you have an air compressor, that can work better than those air cans. What my main problem is is stained wood. I guess there is nothing you can do about those little puddles of coke that have soaked in on the inside exposed wood. A little soap and water doesn't seem to hurt the wood, but...pay attention to my use of the word "little". I don't wanna be responsible if you decide to car wash your cabinet.
PCBs I've done the bathtub method...but every time this topic comes up, everyone and their Mom jumps in about this being either totally fine or completely idiotic. The only boards I've "ruined" giving them a bath were boards where my little hand drawn chip map got destroyed and I couldn't figure out which rom went where.