Use small bottle caps for small stamps and tin lids for huge ones!
You'll need a bottle cap and a small piece of foam for each stamper you want to make.
Draw around the bottle cap on to a piece of paper, this will give you an idea of the space you have to work in.
Draw your stamp design inside the circle. The simpler you make the design, the easier it will be to make in to a stamp.
Cut out your design.
Draw around you design on to the foam, adding on the details.
Cut out the stamper design using scissors and an exacto knife for the details.
Glue the foam shape on to the bottle cap, get an ink pad and you're ready to start stamping!