I'm happy to hear your Sea Mist hasn't changed. I just got a Coach Sea Green (very pale mint) and Chalk and realized I have no idea how to care for light colored bags!
I recommend using Apple Guard Rain and Stain spray for the lighter color bags if they hang lower and will be prone to color transfer. The spray helps from any transfer to be permanent and it comes off with a baby wipe.
https://www.amazon.com/Apple-Repell...17197744&sr=8-3&keywords=apple+rain+and+stain