Sounds like you are definitely on the flight path of bees
I would say to use a couple of options.
I have bought a pack of ordinary kitchen pads, You know, the abrasive ones you can use for washing up, doesn't scratch glass.
Using an Unger squeegee grip (the stainless steel ones with the serated bit that grips the rubber) I have folded a couple of them up and pinched them tight in the squeegee handle.
Works a treat too, might be very 'Heath Robinson', but you can pop it on the ind of an extention pole and scrub over offending windows.
Either that or get hold of the Unger 4 inch knife, these can be gripped in most squeegee handles, stick it on an extention pole and use that.
Omnipole do a range of attachments for cleaning things like cladding, more agressive than a normal brush, so if you have a suitable pole, you could try that too, I see the link is already in place for omnipole in a previous reply, so I won't add it
Shiner,
I use Unger poles for WFP, and the scrapers will fit on them no problem
Regards,
Ian
Poll