I don’t believe Luke is saying avoid forever as they do CCUs themselves.
The thing about CCUs is there is a lot that can go wrong and experience being a regular window cleaner for a while will help you know what to expect on a job.
Window cleaning seems like an easy enough concept, but there are a ton of gotchas in it.
New glass can have fabrication debris that comes right from the factory due to the way they heat treat it. They deny and deny this, but it’s verifiable under a microscope. In these cases, you might do everything right with a scraper and still scratch it.
Concrete and stucco are often on CCU glass and they’re aggregates which will scratch the glass if they’re not removed properly.
You need to know the solvents you use to remove epoxy from a window sill (for instance) are going to be safe for the window gaskets or use them extremely carefully.
You need to know what kind of glass you’re working on. Sometimes tempered glass is put in places you wouldn’t expect and a scraper scratches it right up.
Do some research on different manufacturers and find out what their recommended cleaning methods are. What I know from carpet cleaning is if you clean something in a way the manufacturer disagrees with, insurance will wash their hands of it.
I totally appreciate what you’re saying about not avoiding the issue. Fear should not dictate our decisions, but CCUs are high risk and mistakes can cost tens of thousands or more. That’s exactly why we’re in business, we take on risks others don’t want to, but we should be calculated about our risk taking.