He soon incorporated whale oil into the formula, although many changes have been made over the years. Rust-Oleum products no longer contain whale oil, instead using resins derived from alkyds, polyurethanes, epoxies, latex, etc.
Initially incorporating whale oil into the formula, he later modified it extensively. Rust-Oleum products now exclude whale oil in favor of resins sourced from alkyds, polyurethanes, epoxies, and other materials like latex.