You will need to cut the inner tubing.
To cut the bicycle inner tube cut the center through 2 of the layers to make 2 ends instead of having a circle.
Then cut right down the center and then trim to even the edge and cut off the inner tube spout.
Next cut the inner tube in half but don't cut the side where the spout is, you want the spout to be centered so it can be used for a closure.
For the skull and bones purse fold the inner tube in half so the spout falls at one end and cut the opposite end to make 2 ends instead of a circle.
Used inner tube linings need cleaned before you paint them.
Clean with soap and water.
Make sure they are completely dried.
Paint both the bicycle inner tube and the larger inner tube.