It's always a good idea to keep the valuables in your car hidden from prying eyes. This simple DIY setup requires only an empty mint case and the bottom of an old mouse pad.
This build from WonderHowTo user Nextraker does a good job of concealing your small valuables, such as cash, jewellery or keys. Grab an empty mint container (the round kind) and check to see if it fits in one of your cup holders. Now grab an old mouse pad and cut it to the same size as the container. Put some valuables in there and drop it into your car's cup holder. If someone looked in your window or broke in, they probably wouldn't be able to find it. For complete instructions, check out the link below.
How to Make a Secret Car Compartment [WonderHowTo]