Is cardboard allowed in flammable cabinets?

Excuse me, I'm curious about a specific safety guideline. The paragraph mentions flammable cabinets and raises the question of whether cardboard is permitted within them. Could you please clarify if cardboard is indeed allowed inside these cabinets, considering their flammable nature and the potential risks associated with storing combustible materials together? It's important to ensure compliance with safety regulations and avoid any unforeseen hazards. Thank you for your assistance in clarifying this matter.