What is not permitted to be done to planks used for scaffolding?

Using oil-based paint or sealant on planks used for scaffolding is not permitted due to safety concerns. Oil-based substances can create a slippery surface, which increases the risk of accidents for workers who are using the scaffolding. Additionally, oil-based products may not properly adhere to wood, potentially leading to deterioration of the material and reducing the overall strength and stability of the scaffolding system.

On the other hand, options like applying waterproof sealant and cutting planks for size adjustments can be acceptable practices when done properly, as they can enhance durability and customize the scaffolding to fit specific needs. Painting with non-oil based paint is also generally considered safe and can help to protect the wood without compromising traction.