I have a homemade taryn made from a shoe lace and a rubber pencil grip.It works great. I usually only use the taryn on the first fill, after that I simply drip fill.
In response to posts with tight draw. When this happens I use a paper clip and slowly reopen the air tube, working from both sides. eventually you'll be able to stick the paper clip all the way through. When your finished it'll be like having a fresh carto again.