AAA will make you a credit card access key for free. Perfect answer to your need since it's an emergency only key rather then a key you would be using a lot.
Or, if you really want an out of sight out of mind location for a key you could actually use after regaining entry, just put the key you had made in an envelope (thus avoiding your magnetic concern) and tape to the back of the glove box. You can access the back in the same manner as if you're were changing out the cabin filter. Just press in on the back upper corners and work it out.
2010 Compass LTD Added UConnect w/IPhone cable, front/rear MOPAR mud flaps, K&N drop in air filter, hardmount gooseneck cell phone station, MOPAR cargo liner, MOPAR cargo net, remote Radar Detector w/Voltmeter readout, upgraded speakers/added Tweeters & sub-woofer, MOPAR Back-up Camera/monitor, front lower grill, interior wood accents