Go for it windie.
I have 14 sites that I do stock and show homes, 2 of which I sub out. 5 of these site I also do the build cleans and love it. At any 1 time I've got a backlog of build cleans I can drop on when it's raining / snowing or whatever.
I'm certainly not earning the £60 per hour you hear quoted on here sometimes for this work, but it is good solid work and pays every month at the same time on the dot.
Let everyone keep saying "steer well clear" and "avoid build cleans like the plague" etc, that's what I want them to say!

Oh and since I've been looking after these sites since October, I havnt had to remove a single bit of silicone! Silicone has long been banned from using near windows on these sites.