noooooooooooooooo this just makes it worse for the next frost, you need to spray silicon spray into lock itself and the opening button, honestly you do that 2/3 times over winter months and you will never suffer from any of this
ooohhh and lightly wipe it around the door rubber seal also
I second this, silicone spray is the preventative maintenance, perhaps even silicone grease to last more than a month or two.
We only get a frost a few days a year here so I know what you're thinking, but I go snowboarding in the mountains and on occasion have had to leave my cars parked in heavy snow. Silicone spray in the latch, around the door seals, and in the lock - it's the only way I've found to prevent it all icing up and prevent broken handles, jammed locks, etc. (the first year was a drama, but I've learned...)
I also learned to leave the handbrake off and park in gear, and not to use my credit card for scraping the snow and ice off - it split and the magnetic strip wouldn't work. Might not be a problem with chip cards
I just use one of those loyalty cards instead.
I think I'd also keep a small butane torch on hand just in case - you can get a design known as a 'hot blower' (no flame) which would heat up and defrost a lock in seconds without adding water and without melting the plastic if you're careful. Something like this, with the soldering iron tip removed. http://www.ebay.co.uk/itm/Soldering-...-/280553623086
The better ones self-ignite, like this: http://www.amazon.com/Power-Probe-PP.../dp/B001DIE9BO
which I guess would be handier if you don't happen to have a lighter in your pocket. Difficult, by the way, to get a lighter flame to play against the lock properly.
I guess if a power point is nearby, you could use a hairdrier