A lot of people here use baking soda for other uses, so it is very available. Comes in 250 g, 500 g or 1 kilo boxes, mostly, in the grocery. People put a box in the fridge, opened, to absorb odours. Also, some people brush their teeth with it. It's a less chemical cleaner, too, for scrubbing enamel washbasins, etc. I always used to put a bit in when I washed the baby's stuff - makes it smell better. And of course, the most fun use - you mix it with vinegar to make a volcano!