Hi Donna, I had a similar experience – where my thin layer dried in 6 hours and the thick layer began drying in areas around 8 hours plus. I’m envious of your Grand Cayman life where you can pick mangos off the tree and recognize you likely live in a humid environment. The weather report says 72% humidity today (yikes!) so I recommend you persist as long as it takes. The color does dull when you dehydrate mango naturally as it gets exposed to oxygen (to be expected). I think you will be happy with the result if you keep at it, but as a fail-safe, please email me a photo at sara@thefrayedapron.com so I can take a look at what you’ve got going on. I can usually tell by appearance how much longer you have to go with how wet/tacky it looks:)