[Halcyon]

Crikey that is dusty !!!

You are definately right in saying that it pumps up the temperature.
I did mine just before the temperatures were getting hotter in the summer.
I cut my temperatures down by about 10 degrees just cleaning up the dust.

It takes a while but it is worth it.
I use cotton wool ear buds to clean inside the fans. You often think they are clean but the fan blades are covered in sticky dust.