My window seems to leak a yellow substance on the inside of the frame when it is raining, it then remains sticky where the join is

Ann Hodgkiss, October 2006

Anne
It may be a screw inside the extrusion rusting or metal swaf
rusting. The acid in the silcone attacks screw head causing yellow stains (some times ) not much you can do, clean with cif.

david 30yrs a d/glazer, October 2006

Ann. There is no yellow substance added to window extrusion during the manufacturing process. An outside possibility is that some joker stuffed a sweet into it before it was 'V' cut, bent and welded.. More worryingly though is how it is getting out.
Kev@K.L.Plastics

Kev, October 2006