In case of a skin contact emergency with a Class 8 corrosive substance, what first aid action is recommended on the Instructions in Writing?

1. Apply a thick layer of grease or oil to block the chemical
2. Flush the affected skin area immediately with plenty of clean water for at least 15-20 minutes and remove contaminated clothing
3. Wrap the skin in tight plastic wrap without washing
4. Rub the area vigorously with dry paper towels