I use colored indicator silica beads for desiccant purposes and when the indicator shows they're "wet"/green, I spread them evenly on a baking sheet with foil and bake them at the recommended temp, stirring occasionally, until they turn back orange.

You can buy a purpose-built device like one of these:

https://www.amazon.com/Improved-Eva-dry-333-Renewable-Dehumi...

https://evadry.wpengine.com/product/e-500-renewable-high-cap...

We bake it on low temperature for like two hours. We did it just once, so we cannot assess whether it's still efficient with the baking energy included.

But the winter is coming now, so the extra heat generated when regenerating won't go to waste.

Yep. Just bake them in the oven on low to dehydrate them.