Apparently there are so many t-shirts in the world already that the used ones are doomed after leaving your closet. I stopped buying t-shirts some years ago after realising I wasn't able to find any use for the old ones. Yet I have bought recycled t-shirt yarn to crochet carpets. I think that connecting tricot strips to yarn is an awful lot of work. I'm an active lazy. With a pile of t-shirts in decent condition and a tight wasteline I had to start cutting strips.
First I washed all t-shirts in 60°C and gave them a good spin to tighten the fabric and avoid further shrinking. I cut off all seams, sleeves and collar. Then I folded the fabric from the middle section to make the the piece narrow enough to be cut with one smooth sweep of rotary cutter. I used a regular ruler in the beginning and surprisingly had small wood chips laying around. Feeling lazy I didn't bother to get a proper cutting ruler from another room. After all, it's just t-shirt yarn and the width is supposed to be varying. Starting from one edge I left 3/4 inch uncut and continued making every other cut to opposite direction. The front and back pieces became one long yarn each.
Now I had a bucket of t-shirt yarn instead of the t-shirt pile. Crocheting something started to seem inevitable. There is a limit to crocheted carpets in one home so I decided to make a bag. Since there is no limit to bags.
I used a pink cotton warp yarn from the very beginning hoping to add strenght to the bag. The size of the bag was pretty much determined by the amount of the yarn. There was no obvious place to attach a bag handle cause t-shirt yarn is known to stretch and wear and tear. I had black woven cotton ribbon from old shorts and metal rectangle buckles that I sew in place with enforced polyester thread. The shoulder strap from an old Longchamp bag finally found a new purpose and saved me a lot of effort with easy rotating metal hooks.