That's pretty much the best advice I can give you. Although there are commercial cat repellants, I've never heard of anyone having much success with them. Do the cats use litter boxes indoors also? If so, you might try putting a couple of them near the sandbox, as a "hint." Otherwise, your only recourse is to get a cover for the sandbox when your children aren't using it, or to keep the cats indoors, which is really safer for them, for a number of reasons. Please see the two related FAQs under "Suggested Reading" in the sidebar, for more information

