You pretty much do not need silicone
spray on an AEG ever unless you are doing specialized cleaning. For example, to clean out some bearings which had been exposed to a ton of dirt, I soaked them in a shallow bath of silicone spray and shook vigorously. For lubrication though, don't use silicone spray.
For some insane reason, many AEG manuals have diagrams of spraying silicone into your hopup. This is not useful at all because it lubricates the surface of your bucking, ensuring that your accuracy will suck. There are better ways of cleaning your hopup and bucking chamber *without* spraying them down with silicone.
Some people will counter this by saying that it's okay to spray your hopup with silicone as long as you fire a few hundred BBs through it afterwards, but that's just a waste of BBs since you've just sprayed silicone into your chamber only to try to madly remove it.
Keep the spray away from your AEG. Just get a tube of Superlube and you're good to go for pretty much everything.
A tube like this will last you almost forever:
http://www.ebay.ca/itm/SYNTHETIC-SUP...#ht_500wt_1081