An apparatus (10) for a lorry-based concrete mixer (12) is described. The apparatus (10) comprises a vessel (14) adapted to be positioned beneath a concrete mixer discharge chute portion (16), the vessel (14) comprising a vessel body (18), the vessel body (18) defining a vessel inlet (20) and a vessel outlet (22), the vessel inlet (20) being adapted to receive debris and fluid exiting the chute discharge portion (16), and the vessel outlet (22) being adapted to permit debris and fluid stored in the vessel body (18) to be discharged from the vessel body (18). There is a direct line of sight (24) for a user (26) through the vessel inlet (20) to the vessel outlet (22).