Bill - If you're going to be using sulfuric, look for a lab supply place and get some stuff called "NoChromix" - http://godax.com/
You add a packet of the stuff to conc. sulfuric acid and then you just soak the glass in the Nochromix/sulfuric solution. It will clean most everything off glass - given enough time. We used to use it in a lab I worked in as a replacement for dichromic acid/sulfuric acid solution which was the traditional lab glass cleaning solution.
Plan ahead and let your glass soak and you'll never have to scrub glass again.