I think we already have some of that..........(rushes off to check), yep, in the kitchen cleaning cupboard.

Now all I need is some warmer dry weather...........

 

lol well im a window cleaner and i generally just get it right the first time so take it back and get them to do it again as said above,

 

The best thing to use first is a IPA wipe down its like an alcohol based solution that you dilute down 50/50 (not for drinking) simply spray on and wipe with microfiber cloth, this will remove all the grease finger prints and any other products used. Then any good glass cleaner will have good results I use this currently and its great ( Dodo Juice - Clearly Menthol Glass Cleaner 500ml £7.95)