i've read alot about not using it and some saying they used their sand again. so i'll chime in here for ya, from own personal experience...i've done it at least 3 times without incident, not even a hiccup. i rinsed very well till there was virtually nothing left to rinse and voila!! hope this helps.
oh yeah, don't forget that the sand you're paying $30/bag for has been used before already

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