If the scrap of yarn is three inches or longer, it gets tied in with an overhand knot. The ‘tails’ are between three-eighths and three-quarters of an inch long, and they will remain.

I’ve picked out a pattern, but I still have many, many bits of yarn to tie into the ball. It’s slow going, because many of the scraps my knitting buddies give me are not sorted as to fibre content. I have to do a burn test to sort out the wool yarns; I don’t want my vest to be a hand-wash-only item!
I printed out the pattern in the late 90s or early 2000s, when it was free.