The best replacement for hand warmers is oxygen absorbers.

The best alternatives to hand warmers are rated as following:
★★★★★  oxygen absorbers
★★★  sanyo hand warmers

Your alternative for hand warmers is not listed? Suggest!
Speaking about hand warmers, one probably shouldn't forget about gloves.

Other search terms related to hand warmers and their ratings are:
★★★★★ gloves
You have in mind a companion for hand warmers and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of hand warmers in all years. Click on graph for more.
hand warmers
oxygen absorbers
sanyo hand warmers