Anybody use old substrate as mulch in the garden? What kinds?

Repti-bark, coco husk, and cypress mulch all basically look like mulch anyway... anyone mulch the garden with them after the snake's done with them? (If so, do you do it with chunks of poop/urate in there too?) How about aspen, besides not looking as nice? Presumably if these things are fine for the snake to live in, they're fine for the garden afterward, right?
If so, what do you do with when the ground is covered in snow? Leave it in a pile somewhere and spread it around later when the snow's gone?

I throw the soiled cypress and aspen mulch onto the veggie garden in the back yard on the days I do a full clean-out and replacement of the substrate. Anything picked up during spot cleaning just goes into the trash.

If there is snow on the ground I just spread it on top of the snow. Eventually the snow will melt.

I do, it's natural fertilizer works great when you have a vegetable garden or prepare the soil for the next spring.

Don't have snow often I live in north GA and have seen snow that stayed (2 days) twice in 15 years so I cannot comment on that.