c/p courtesy of ganjaguru..
I had a male plant that I seperated from the others as soon as it grew balls (2 days after 12/12!). When the balls opened and it began to shed pollen I put a small paper bag over a branch that had tons of balls and left it for several days.
Then I removed the bag which by now contained lots of pollen (and ditched the male). I put the paper bag in a tight-sealing container and kept it in a cool dry place for several weeks, then I put the bag over the end of the lowest branch of a female that had developing buds and shook it up, then removed it.
The next day I sprayed the entire female with water which invalidates the unused pollen and set her back in the flowering room with her sisters.
And grew a crop of sinsemilla except for that 1 branch.
Another way to collect pollen is to cut the branch of a male off as soon as it begins to shed pollen (or just before), then put that branch in a glass of water that was sitting on a pane of glass. It will continue to live long enough to shed. Then you can scrape the pollen off the glass into a paper bag, and when ready, use a small paint brush to paint pollen onto the chose branch(es).
Of course, there should be NO air circulation during collection & pollination.
