Sun Drying-Ditzy Question

I am blonde so I am going to blame this question on being ditzy sometimes. 

So I tried to sun my inserts that I have used all winter and not had the chance to sun before.  I laid them out on my deck railing soaking wet from the wash machine. Because of the wind I had to wrap them on so I wouldn't lose them.  They were they for over 5 hours and some still seemed a little damp and I am guessing the back sides that didn't see the sun were still wet.  I re-wet them with a pitcher of water and let them sit till past dark.  When I brought them in I noticed that I could still see the stains on the top side that I had tried to sun on most.

So what did I do wrong? Do you have to let them completely dry to get the stains out.  Do they just need more time since they were large washed in stains. Does it not work when you lay them flat on the deck only when on a line for air circulation. Something else?

Most of them are Flip stay dry inserts if that matters. They are both EBF and BM/Solid stains.