a56d19bc_A_Practical_Guide_to_First_Aid__Chemical
[Route of Exposure] Skin contact [Suggested Recommendations] These metals can ignite spontaneously on contact with moisture, and react exothermically with water to form very corrosive sodium and potassium hydroxides. Avoid direct contact. Wear chemical protective clothing, if necessary. Take off immediately contaminated clothing and store it in a non-combustible container under mineral oil. DO NOT flush affected area with water. Use a class D fire extinguisher or sand to suppress flames. Then, cover any metal fragments embedded in the skin with non-toxic mineral oil or cooking oil and transport victim to an emergency care facility. (Edlich et al. 2005, Krenzelok, 2001) [Chemical] 
Elemental sodium and potassium.
CCOHS: Products & Services: The MSDS - A Practical Guide to First Aid
Chemical