Hi Lulu (lynn),
For what its worth, I contacted a company in the states that made a machine to do the job a few years ago, where i asked the same question!
Basically they said as a stand alone business it is not viable, only as a add-on to your existing cleaning business.
In my opinion its not the sort of cleaning that needs doing every day, in other words its a good idea, but i think you will be hard pushed to find regular work with this sort of niche cleaning.
Although if you do go ahead and have ago, i would direct mail `Facilities Managers` and then follow up with a personal call to get work. where by you could arrange a test clean.
I will try and find out the name of the company and its web-site if you are interested.
Good luck, and let us know how you get on!
keith