Rinse it really well. Dry it really well.
When you need it you should cure it by running it in a tank for a week stirring up the sand frequently.
Test your water and do any changes until it is good.
That is what I used. I rinsed it thoroughly with fresh water from a hose.
Once I was ready to reuse it I just used freshly made RODI saltwater to start the process in a spare 40 breeder I have.
The important part of this is to stir up the sand and test the water to make sure it is safe to use. When I started this part I did notice some nitrites but they went away in a couple days. I did a water change and everything was optimal.