Stage 0	General Description       No apparent rust. No visible corrosion, paint discoloration (not caused by corrosion) is permissible. Painted Surfaces       Interior Machine Surface (Both Functional and Non-Functional)       Exterior Machine Surface (Both Functional and Non-Functional)       Remarks
Stage 1	General Description       Discoloration staining; no direct visual evid- ence of pitting, or other surface damage Painted Surfaces       This condition does not require immediate corrective action. Interior Machine Surface (Both Functional and Non-Functional)       This condition does not require immediate action other than re- processing as necessary Exterior Machine Surface (Both Functional and Non-Functional)       This condition does not require immediate action other than re- processing as necessary Remarks       Use as is, except in the case of elevating cylinders subjected to functional wiping action. Remove corrosion using crocus doth
Stage 2	General Description       Loose rust, black or white corrosion accompanied by minor etching, and pitting of surface. No scale or tight rust. Painted Surfaces       Clean by any appli- cable process. Touch up with paint as originally applied. Interior Machine Surface (Both Functional and Non-Functional)       Clean, exercise, and reprocess. Exterior Machine Surface (Both Functional and Non-Functional)       Clean, exercise, and reprocess Remarks       In the case of elevat- ing cylinders sub- jected to functional wiping action, remove corrosion by use of crocus cloth.
Stage 3	General Description       Rust, black or white corrosion accom- panied singularly or in - combination with etching, pitting, or - more extensive sur- face damage. Loose or granular condition. Painted Surfaces       Clean by any appli- cable process. Touch up with paint as originally applied. Interior Machine Surface (Both Functional and Non-Functional)       Exercise and reprocess Exterior Machine Surface (Both Functional and Non-Functional)       Clean, exercise, and reprocess Remarks       This condition would have minor effect on fit or wear of paint or component but would permit use without reprocess. Does not apply to such items as instruments (elec- trical or manual) and critical surfaces that are necessary to effect a seal against pressurized liquids.
Stage 4	General Description       Rust, black or white corrosion progressed to the point where fit. wear, function life of the item have been affected. Powdered or scaly condition with pits or irregular areas of material removed from surface of item. Painted Surfaces       Clean by any applicable process. Touch up with paint as originally applied. Interior Machine Surface (Both Functional and Non-Functional)       Replace or rework and components involved. Exterior Machine Surface (Both Functional and Non-Functional)       Replace or rework parts and components involved. Remarks       This condition will require action as indicated.
NOTE: - This information was taken from Technical Manual TM 38-470 "Storage and Maintenance of Army Prepositioned Stock Material 15 June 2001