I was only an apprentice plumber so any pros can check my answer.

That being said, the company I worked for did only service work, that being only repairs or R&R's when something couldn't be fixed or cleaned out, such as drains.

1/2 of my work in the first 6 months was clearing drains, either by plunger, auger, or taking apart pipes.

I never particularly noticed if a drain had been treated with chemicals, but my company taught me not to use them and to recommend them because they damaged the interior of the pipes leading to further problems such as waste sticking to the scarred inside of the pipe, or even damage that required replacement if the drains at some point.

Nothing was specified to apply only to copper or brass or ABS or PVC, so I can't be more specific about that.