Some people need to use new sand if they can’t recycle enough clean sand, says Dave Bray, dairy extension specialist at the University of Florida. If your recycled sand smells like “earth,” it’s good to be used. If it smells like manure, let it sit and drain. When it drains and if it smells like “earth,” use it.

If your sand smells like manure and has to heat, spread it on the fields — it’s fertilizer, says Bray.