Spray lubing is definitely the lazy way of lubing a switch without desoldering it, its basically applying a thin layer of lube (normally PTFE) onto the inside. I've done it before with some cheap outemu reds and it made the spring ping noise go away. However it is really hard to control how much lube goes into the switch, therefore hard to get an even layer of lube. I would say it is fairly safe, but since the lube is still liquid, and lube is still lube, don't apply too much. However there is still a chance that you can ruin your switch and PCB by doing so. If you do end up spray lubing, I'd recommend using Super Lube's MULTI-PURPOSE SYNTHETIC LUBRICANT WITH SYNCOLON® (PTFE) or WD-40's Dry PTFE Lubricant. I haven't tried any other lubricants but that does not mean they are not safe to use. If you do want to look for other lubricants, i suggest you look for something that is "dry" and "PTFE". When finished lubing, try flip the keyboard so that the excess lube can escape.
