This is a hit or miss opportunity if you can do it good on you not for me though,in my area some guys where about using a large van just after the bins appeared on a local council estate but Iv not seen em since after only 2-3 months maybe the work wasnt there ? may have been the very business which was up for sale around the same time soon after not seeing them again

There is another guy about I more often see his car parked not working so guess unlike windows some people may just get them done a few times or once only as they dont look at them the same way as window cleaning.
I think there is a big call for this in my area, in peterborough there is well established businesses and if you look on ebay i see business going along with £1000 of work per month, i think waht puts people off is the smell

dificulty collecting money, not unlike window cleaning can be, plus licences and conditions of what is done with water in some area including mine. if you look up bin cleaning trailors, van etc, they are very expensive. I am going to build my own which will cost a fraction of them and do the same job. also only doing this as add on 1 maybe 2 days per week, see what happens