Oh, I know about this. I did rinse them thoroughly. Then I used a few drops of Dawn dish detergent to wash them. But what I found was that even if you clean plastic lenses thoroughly, what counts is how you dry them. If you use paper or even a towel it can scratch them incrementally over time.

It's so much more convenient (or maybe I'm just lazy!) to be able to dry glass lenses with a towel, paper towel, a t-shirt, or anything absorbent.