Final answer:
The nurse should instruct the mothers to 1) remove the contaminated clothing immediately and 2) flood the area with lukewarm water. They should then wash the area with soap and water and call the nearest poison control center.
Step-by-step explanation:
The nurse should instruct the mothers to remove the contaminated clothing immediately if poison comes in contact with their child's clothing and skin. This is because removing the clothing can help minimize further exposure to the poison. After removing the clothing, the contaminated area should be flooded with lukewarm water to rinse off any remaining residue.
While washing the contaminated area with soap and water is important, it should be done after removing the clothing and flooding the area with water. This ensures that the initial priority of minimizing exposure to the poison is addressed first. Lastly, the nurse should instruct the mothers to call the nearest poison control center immediately for further guidance and assistance.