Decal says: DONALDSON COLLECTORS PRE-CLEANER CAUTION-SERVICE OIL WASHED CLEANER DAILY BECAUSE PRE-CLEANER REMOVES ONLY PART OF DIRT. EMPTY PRE-CLEANER JAR WHEN JAR IS 3/4 FULL OCCASIONALLY REMOVE PRE-CLEANER AND WASH IN KEROSENE. ALSO REMOVE OIL CUP FROM OIL WASHED AIR CLEANER AND SCRAPE DIRT FROM FULL LENGTH OF INLET TUBE. MFG UNDER ONE OR MORE PATENT NOS 1513035, 153036, 1556592, 1641746, 1755319, 1850343, 1761923, 1461174, 1734030, 1665434, 1669104, 1464741, OTHER PAT . PEND MFD. BY DONALDSON CO., INC, ST. PAUL MADE IN U.S.A.