Our school collects pop-can pull tabs every year. Why collect the tabs and not the cans?

Many people believe that the pull-tabs (or cigarette celophane pull-strings) can be redeemed for special medical help for the ill. This is an urban legend (see below). The entire can would provide much more scrap aluminum. Tell people at your school that they have been scammed.

I dont think the point of the exercise is to collect scrap metal, but rather to do some (almost meaningless) task in hopes of having a sponsor pay them for the effort.

For example, if some company (or individual) feels generous and wants to make a charitable donation, what they could say to your school is "for every soda can tab you collect, I will donate $.001 to your school". So then the school tries to collect as many tabs as possible in order to get the largest donation....the fact that the tabs are Aluminum is imaterial, it could just as easily be gum wrappers or elephants for that matter. Soda tabs are easy since kids drink a lot of soda and they are easy to store and count.

This, of course, all depends upon the participation of some generous sponsor who is willing to pay a considerable markup on what might ordinarily be trash [or at leat recycle material].

Ease of effort in collection and moving. To collect cans, one has to crush them to get the air out. Salvage places have learned that air DOES have weight and want to pay you for aluminum, not air. Who wants to go through the effort of crushing every can instead of just tossing it into the collection bin. Plus say 500 pull tabs are a lot less bulky and therefore easier to move, handle than 500 crushed cans.