++1
Works, Cheep, and always available
But if you are squeamish about using spit, checkout diving shops or motorcycle (think sportbikes and parts shops) shops for products to prevent foging.
This is the can I use for myself and my company uses them in the field. No problems leaking and durable. They are around $40+ but worth it in my opinion.
You can get them at many stores, like lowes...
BTW First post... cool site.. been lurking for a while