A USCG bulletin flags a misprint in the Oil Record Book CG-4602A: manual collection of oil residue (sludge) should be recorded with code C11, not the printed C12.
The examples, provided on page 13 of CG-4602A, for recording oil residue (sludge) collected by manual operation utilize the incorrect item number, "C12". Collection of oil residue (sludge) by manual operation should instead be recorded with code/number "C11".
Source: USCG