I guess Instructablers are really green generally so you will like this way to recycle the dead umbrellas and at the same time have handy compact shopping bags so that you never need a plastic supermarket bag ever again. They roll up so small you can keep one in the pocket of each coat and handbag.
Step 1: What you will need
These are very easily come by, especially in city centres in wet windy weather. In one week I gathered over 30 umbrellas on the 2 minute walk from my home to the station and the 10 minute walk from the station to my office in the city centre. I just helped myself to the umbrellas jammed into the public waste bins.
Here in Glasgow the small, telescopic umbrellas are popular and the majority of that type are black. I ended up with loads of them and, to avoid making a million small black boring bags, I used a lot of them either for lining some bags or for making handle strips. If you dont do that then you will need something to make handles or straps from: tape, bootlaces, string even.