Tips (and frogs?!)
If your violin gets really cold (frozen), do NOT put it somewhere warm. The wood need to gradually warm up, so put it in the porch for a few hours first, and then gradually move it to somewhere room temperature where you should leave it in it's case for a nother hour or so. The best thing is to never let your violin freeze or get too hot!
If you want to humidify your instrument you can put a lemon in the case and replace it when it gets shrivelled, or put a damp sponge into a zip-lock bag and poke the bag with a pin so it has a bunch of breathing holes and leave it in your case. Or you can buy a fancy humidifying contraption at a music store!