I used green (raw) papaya last Saturday - using the seeds and the skin. I juiced them. Raw papaya is very dry in the center in the seeds area. The seeds are small white 'nubs' and I don't think you can extract anything from them if you still dried them .
Maybe sun-drying is for the ripe (yellow) papaya seeds? As they are wet/slimy, with this gel-like coating? But I also tried the ripe seeds (so I hope they're not poisonous!). Disappointingly, I got more with the raw seeds than the ripe ones. I'm not sure if I already got most of them out, or the ripe ones simply don't work as well. So I'm trying the raw seeds again next week, after I tried the pineapples :)