Strychnine is ahighly poisonous natural substancethat is used in some countries for the control of wild animals. Today, strychnine is used primarily as a pesticide, particularly to kill rats.
Most insects are repelled by thesmell of vinegar. Spray the inside and outside of the sandbox, as well as the sand, with undiluted white-distilled or apple cider vinegar, and allow the vinegar to dry before playing in the sand. Citronella oil added to the sandbox will also help repel bu...