If you build the body of the wallet around aluminum foil, it will shield radio-frequency identification (RFID) credit cards from being cloned.
You can make your bill fold a little higher so it's easy to open.
To make a flap to protect your bills: take one length of duct tape the width of your wallet, stick about a quarter of it on the back, fold it over itself so there is no stickiness, and then fold it down the inside of your wallet. Now your money can’t fall out.
Don't use good scissors when cutting the tape; you'll get adhesive on the blades which will compromise their cutting effectiveness.
If you see any bubbles, get a needle and pop them, then touch it gently.
Some cutting hints:
If cutting the duct tape with scissors, it is easier to make small cuts rather than large cuts.
Putting butter or margarine on your scissors can help make cutting the duct tape easier.
If you are using a knife, a metal or metal-edged ruler is best.
Have some bank notes and credit cards handy as you're making your wallet so you can make sure everything is the right size.
Make sure your ends are even.
If you are going to cut the duct tape with scissors, it would be easier to use non-stick scissors.
There are many ways to personalize this design. Consider:
Adding coin pockets within the large bill pocket or placing flaps on the credit card holders so business cards don't fall out if the wallet is dropped.
Experimenting with different colors. Duct tape comes in colors too; try using a different color for the internal flaps. Or, Black Tyvek tape is available in 2 and 4 inch (5 and 10cm) widths from book binding suppliers for a nice, low-key look.
Using clear packing tape. To provide some more structure--and a little bit of color--put photos or colored paper between the layers of tape.
Using paper, cloth, fishnet, or painter's tape (blue tape)....