Sorry they don't make artificial limbs from ring pulls

It is widely believed that charities collect these tabs to be made into prosthetic limbs. This was true a decade ago but today is no longer the case. In the region, it was a Thai charity (Prostheses Foundation of HRH the Princess Mother's) that once asked for such donations. However they have been asking people to stop sending tabs FOR YEARS.

Improvements in materials for prostheses as well as ISO standards means this aluminum is no longer used. Sending aluminum is also an inefficient method to make donations and burdens them with the task of taking the metal to scrap dealers. So they now ask donors who make such collections to sell the metal and send them the cash raised.  This is easier for them and avoids all the costs of shipping and handling.

Most people are unaware of this because the info coming from the charity is almost all in Thai (and honestly, without the technology of Google Image translate, their infographic makes it look like they still take tabs. But really they don't).

tl;dr: Want to support them? Send cash. 

Did you know? 

Aluminum can be recycled infinitely. But that does not mean it is perfect. Manufacturing and even recycling of aluminum produces toxic byproducts that are difficult to deal with and is extremely energy intensive.

Manufacturing

• Mining of bauxite and other raw materials releases toxins into the environment.
• Manufacturing is harmful to the environment and to the people who live near the mining, refining, or smelting operations.
• It takes a lot of energy to produce aluminum

Recycling

• Recycling aluminum produces chemicals that may be released into the air.
• It also produces a waste product called "dross" that is highly toxic and has to be buried in landfills. This dross must be tightly sealed in containers so that it doesn’t leak out and enter groundwater. Aluminum dross has caused serious environmental and public health challenges.