This may be a silly question,, but can you take sphagnum moss and dry it out after cuttings have rooted then save it to use again ??

I re-use mine.
Seems to dry up quick if left unsealed.

i sterilize mine for 1.5 min in the micro b4 re-using.

I recycle them in rooting for the season. They dry up easy like Rafed said. When they are not needed they end up in-ground.

I would think that sterilizing would kill the benefits of the moss.
I have reused mine also. Works well but eventually I use new.

Peg

Like Paul said,

I also like to mix a little with the potting mix to help keep it moist during the hot Summer months.
At least I'm hoping it stays moist in the mix?

I have re-used mine with no problem and nothing special done between uses.