The switches aren't air tight. You can reach almost all areas from the top. It's just not precise and more messy. Surely you didn't mean it's impossible.
Thanks for the info on alcohol. It sounds right. Though a bit costly because if they are soldered on it might need tons of it.
The lube probably won't reach the areas that need to be lubed. In the "Making stuff together" subforum, there's a guide on how to lube Cherry MX switches. And there's pictures as to where the lube should be applied to. Also, if you just flood the chamber, it isn't airtight like you said, and the lube could get out of the switch and get onto the PCB.
Also the lube that ppl like to put on the switches is the same as the lube on the springs. I'm not sure you will get the same results if you just flood the chamber with one type of lube.
Finally, I think you need to calm down a little. There's no need to attack people in every thread just because some people have an opinion different from yours or say something silly, doesn't mean you need to jump down throats and attack.