The can of Great Stuff foam sealer is clogged at the tip after
one use. In order to unclog it, I will face the can tip down on
a concrete surface and push down on the can with my full
weight. This breaks the seal and the can is reusable. I have
used a paper clip to clean foam off the can's nozzle, but it
doesn't work and doesn't seem safe.

I have a feeling that this can will get stuck forever. Is there
a practical way to prevent it from clogging in the future?

Thanks