The pair take a wander around Bristol in preparation for their gallery selling task, where they stumble upon pieces of graffiti from Nathan Bowen.
"These work for graffiti but you wouldn't put that on your bedroom wall," Martin announced, describing an example of Bowen's work as "a crazy workman alien peeing on another crazy workman alien".
Coming across another, Holzherr admitted that he "wouldn't pay" for the work of art, while Martin agreed that it looks "awful".
Failing to find inspiration in Bowen's pieces, the boys walk away laughing as Holzherr jests: "Shall we carry on?"
The Apprentice airs Wednesdays at 9pm on BBC One.
Watch Ricky and Nick review street art below: