hi there,
our core business is builders cleans (commercial and domestic house builders), absolutely great, its all about building a relationship with the site, the construction directors and the build directors
wooden windows are the worst, warm water,detergrent and a 3m non scratch scourer, job done plaster dissolves away.
at the end of the day, we work with the sites so that we are on site at the correct time, and work with the other trades, to save ourselves the hassle that others have had, like wet paint, no water etc.
regarding scrapers, the unger retractable blade scrapers on wet glass are fantastic for a multitude of sins.
also the site 'plastic surgeon' is also great person to get to know, they know all the tricks.
so if you get it right you can make money
regards
martin