Scott,
I didn't see any visible sheen on the water, from my line or otherwise. I sprayed it at home, so I didn't have overspray and it was totally dry by the time I fished.
I have no clue what concentration of the toxic stuff ends up on the line or in the water, but a note indicating it's "hazardous to the aquatic environment" is less than ideal for a product to use on fishing equipment.
I did some Googling, and saw some folks on random forums recommending 303 Aerospace Protectant. I have some of this and know it's good for PVC, and this safety sheet makes it look quite a bit safer:
https://www.englundmarine.com/SDS/TOT30910.pdf I'll give this a go and report back.
I should also note that I clean my lines in a bowl of hot water and Dawn dish soap occasionally, scrubbing with a soapy microfiber rag and reeling into dry microfiber rag after rinsing. It seems to clean more dirt and stains than any of the fly line cleaners I've used.
Dalton