I let a few of my organic yellow crook neck squash go to seed this year. This is the first time I really let summer squash go to seed and I was really excited to open up those bumpy, big bad boys! When they stayed on the vine they got very textured like a gourd and the skin became hard like a winter squash. I picked them a few weeks ago and then left them in the sun to mature and dry some more. I cut them open today and pulled the good seeds out, placing them on the wooden chop block to fully air dry.
The seeds to save are the ones that are fully formed, mature, hard, and pretty thick. If it's limp and empty on the inside then it's not going to ever do anything. Just one or two squash can yield a pretty high amount of seeds - which is a great money saver for next year's organic garden!
PS- look at my cute little pie pumpkins in the background! Mmmmmmm.