Put the lid back on when you are done. If you store the can upright (in its normal position) it will keep the device from turning on.
A Barreller Bot is a device that has seemingly eternal forward propulsion in a given direction. In other words, there is a motor that acts as an off-centered weight inside of a can. When the can rolls forward in the direction of the weight (the weight, being the motor), the motor turns upwards, hence, causing the can to roll forward again. Now, imagine this happening really quickly and for a sustained amount of time. It would give the can the appearance of rolling forward on its own and even cause it to do seemingly impossible things, like rolling up inclines. This bot is great fun! If you don't believe me, build one for yourself. It is quick and easy to do.
(x1) continuous rotation servo modified for direct drive **
(x1) paint can (or similar)
(x2) 1" paintbrushes
(x1) 4 x AA battery holder
(x4) AA batteries
(x1) tilt switch (Mouser #107-2002-EV)
(x1) assorted zip ties
(x1) template (see below)
**Learn to remove a servo controller board at this page.