Fly screens that have sat in the frame for ten years don't want to come out. Most people end up levering at them with a screwdriver, a butter knife, or whatever's in the van, and put a hole in the mesh or a bend in the frame doing it. 
 
If you clean windows for a living you already know how to remove fly screens. Getting them off shouldn't be the hard part of the job.
 
The leading edge is 0.8mm. Thin enough to slide into gaps where fingers and improvised tools get no purchase at all, including flush-mounted insect screens and velcro-backed frames with no grip point.
 
The body is glass-filled plastic, rigid enough to give you real leverage without flexing. It's plastic and not steel, so you're not dragging metal across an aluminium frame. The matte grip puts your hand in the right position without you thinking about it.
 
At 160mm long and 15mm thick it sits in a tool bag or hangs off a belt loop through the lanyard hole, always handy.
 
Purpose-built for fly screen removal, moulded from our own custom mould. Not a paint scraper with a new label on it.
 
Specs
Length 160mm
Width 73mm at the tip, 45mm at the handle
Height 15mm
Leading edge 0.8mm
Glass-filled plastic body, 2.5 times stronger than the standard ABS screen tool in our own load testing
Matte ergonomic grip
Lanyard hole for belt or tool bag
Designed and tested in Australia