I'm with Jim on this one. When I started out I had the equipment and did the occasional job but hated it.
Solvents are not nice and you should be wearing PPE.
Reasons for not liking the job included that to do the job properly you needed to vacuum both front and back. Now try that whilst using equipment and standing in front of a sunny window and you will get very hot.
And then complicate it further by standing on step ladders.
It's always difficult to vacuum properly the top part where the curtain is gathered as well.
Cats can leave horrible hair/body oil on the linings which are very difficult to remove as well.
Adding it all up you have to be charging a decent whack to cover the time and cost of solvents. When you tell them the price some customers near faint away.
Taking them down and along to a dry cleaners is a possibility or you can simply suggest that the customer does that as the custy doesn't see the hidden cost of the time taken fetching and carrying them to the dry cleaners. Besides dumping them into a vat of dry cleaning fluid will always give a better clean as the whole fabric is immersed and cleaned - a bit like Dave Lionaha's rug cleaning.
So net result is the custy does all the work and pays out less for curtain cleaning and has more money left to clean more carpets whilst you look professional for not trying to take them for every penny of cleaning.
SO there I was with very few curtain cleaning jobs and of those I had to do it was because they would be incredibly difficult to take down, or the client didn't want to be without their privacy at night. (I did do the occasional job where all I did was just vacuum the curtains as often most of the dirt in curtains is the dust that collects in the top foot or so.).
Conclusion. I got rid of my equipment and breathed a huge sigh of relief......
and then for the next month or so I received about 12 enquiries about curtain cleaning