This idea already exists in the USA and Canada for valuable plastics, such as PET water bottles. These programs put monetary value to the plastic bottles. In California for instance, it's called the California Refund Value (CRV). The consumers pay a small fee upon purchase of the beverage and the money goes to a pool held by a state governmental agency called CalRecycle. When a material recovery facility recycles it, they get a few cents per bottle from this fund. The unclaimed money from the fund becomes grants to incentivize new innovation as grants. This program is only feasible for plastics that have a downstream waste market. Since the 3 types of materials named in this challenge do not have downstream markets, it would be very hard to figure out where the money would come from in your currency system. You would need an innovation that can transform your sachets, straws, and tear-offs into valuable materials with markets for this currency system to be implemented.