The disclosure relates to generally to the field of toxin inactivation. More specifically, it relates to clostridial toxins, methods of inactivating these toxins and compositions (e.g., vaccines) comprising toxoids (e.g., produced by these methods). Provided are methods of producing a C. difficile toxoid comprising inactivating a C. difficile toxin with formaldehyde. Toxoids prepared by these methods are stable at high temperature (e.g., 37°C) and remain non-cytotoxic with minimal residual formaldehyde.
