Well I found out it had an aromatic chlorine compound and isopropanol in it, which I figured would be good solvents and it is very cheap. I never realised doing so many chemistry topics in undergrad would actually prove useful.

I have since heard of a few other people on the net using it too, so I can't claim full responsibility.
Spray paint is a bit iffy, there are lots of people that use cheap brands and swear by them as being just as good. GW spray is designed for models, and they claim that the chemicals in it makes it stick better and come out as a finer mist so it doesn't obscure details. Whether you believe that or not is up to you, all I can say is GW spray is expensive but I personally don't want to try others, if you do try a cheaper brand make sure you test it on a model you don't care too much about or a bit of sprue first. You want to make sure it doesn't go on too thick, it isn't lumpy at all, and that GW paints stick to it well. I would probably try a model or hobby store for something before just getting a random can from a hardware store.
Also, be aware that in Aus you need to be 18 to buy spray paint (which is hilarious, these signs sit next to the 'you need to be 16 to by knives' signs

) I'm not sure about where you live though. Last time I checked GW didn't have an age limit for their spray because they say it is water based and comes off really easily anyway plus it is so expensive people won't use it for silly things.