NaOH Waste from Solder Mask Removal

[meatheadmerlin]

I was wondering how to dispose of sodium hydroxide that has been used for removing solder mask.
Has it been contaminated with anything from the solder mask that I should be concerned about?
Would it still be usable to adjust the pH of waste solutions when processing them for disposal?

 

[rewalston]

If I remember correctly, Steve, stated that it can be used to adjust ph. That's what I did last year with mine. Worked fine.

Rusty

 

[MarcoP]

Last time I've used it for solder masks I decanted, quickly filtered and let it evaporate down for easy storage, will then be used for acid waste treatments or for other solder mask removal runs.

Marco