The idea was for tokens that would only be exchangeable
for food, thus ensuring that your donation would not be
used for drugs or alcohol.
The question is whether you'll change things by making
people eat a meal now and then. You won't.*
Many homeless people are simply mentally ill. Mentally
people often do drugs to cope with a mind that just doesn't
work very well. They become addicted, and they use any
further resources to feed this addiction. If you give them
tokens, they will sell them for money, and they will get
away from their minds with the proceeds.
This idea is for a similar system that makes it possible for
your donation to be exchangeable for mental health or
rehab services only. Everyone needs food. Everyone can
take advantage of people who think they don't.
If these tokens are sold, then someone profits only by
having rehab and mental health services. If they're thrown
in the gutter, them someone picks them up and hoards
them for rehab or mental health services.
This would require a system that would allow rehab service
providers to be paid by turning the tokens in.
The tokens would be given charitable tax deductions
similar to other contributions.
* I really do know what I'm talking about.