Update on the bag I was dunking. It's pretty dry now but I'm leaving it to dry for an additional day to make sure there are no damp spots that can lead to mould.
I've decided to dye it black and give it a good conditioning, then put it back in the donation pile. I'm certain it'll be good as new once I'm done with it, but I have 12 black bags so I'd rather release it than keep it.
I'm definitely getting a yellow bag when the right one grabs me. I've posted my goals on the 2021 thread already and in there I said I won't experiment with other brands. If I get a yellow bag, it'll be a vintage Coach, Portland Leather Goods, Hammitt or Massaccessi.
I may wait a few months before actually following through on the yellow bag. I'd like to release a few more from my collection before letting one in, and I already have a lot of colourful bags that I can enjoy until I scratch this particular bag itch.
@whateve Just want to thank you for the info on yellow and bone vintage Coach bags.

It's a bit of a rabbit hole figuring out which vintage bags are which. For instance, the Penny, Pocket Purse and Dinky all look exactly the same to me!

But it's fun to read now and learn all the styles. I'll post in that thread if I end up with a vintage beauty.