After that, use cotton swabs with vinegar or lemon juice.
The acid will neutralize the leaked alkaline material to prevent further corrosion. (If using one of those, wear safety glasses, so you don't flick the solution into your eyes.) Temperature.
This is nice especially given that smoke detector batteries are bothersome to replace. mail and why they can't go in your checked luggage when you fly.
Alkalines aren't nearly as hazardous as Ni Cd's, but they do contain useful metals, and it's better for those metals to be reclaimed by recycling rather than strip-mining mountains. it's tougher: while recycling for Ni MH, Ni Zn, and Ni Cd is widespread (see RBRC), there just aren't nearly as many places to recycle alkalines.
Alkalines perform poorly at subfreezing temperatures (reduced capacity), as this chart from Energizer (PDF) shows.
Nickel Zinc and Lithium are better for below-freezing applications.
Someone on a web forum said that it's possibly to squeeze more life out of seemingly dead alkalines by tapping them against a hard surface, but I have yet to test that theory. So if you do use alkalines, choosing Rayovac or Energizer might afford some measure of insurance.
(I want to call out Duracell for special mention for having especially pathetic customer service.
Alkalines became popular in the 1970's, as a high-capacity replacement for wimpy Carbon Zinc batteries (e.g., "Heavy Duty" and "General Purpose" batteries).