Rust-eze appears on Lightning McQueen's original racing paint scheme in Pixar's Cars.
Rust-eze is a fictional product and sponsor associated with rusty automobile treatments. McQueen begins the first film as a Rust-eze-sponsored rookie competing for the Piston Cup. The sponsor's branding is visible on his red body and helps establish his commercial identity before he becomes a more established champion.
Rust-eze is represented by Rusty and Dusty Rust-eze, the brothers who manage the company. They promise McQueen a Dinoco sponsorship if he wins the Piston Cup, making the rivalry between Rust-eze and Dinoco part of the film's story. McQueen eventually develops a close relationship with Dinoco, but Rust-eze remains central to his career and to the franchise's branding.
Dinoco is therefore a plausible mix-up: it is another important fictional sponsor, not McQueen's original one. Clutch Aid and Octane Gain are also fictional racing brands appearing in the Cars universe.