I have been singing the praises of the wagtail combie for years, I have posted on it many times.
It takes longer to rinse beading glass than to do the job with a wagtail, you just put it on the glass, the washing and blading is done at the same time, one pass job done.
This tool is the best ever for doing insides, it uses very little water.
I can't understand why everyone doesn't use one either.