I unpacked decorations from storage and they’re coated in a strange white film. What happened?

be wise to investigate further.
In most cases, the white film is simply a cosmetic issue and can be cleaned off without concern. However, if you’re unsure about the nature of the residue, consulting a professional can provide peace of mind.
8. The Safest Ways to Clean Different Types of Decorations
Cleaning the white film off decorations depends on the material. For most items, a gentle wipe with a soft cloth dampened with a mild soap solution will suffice. Avoid using harsh chemicals that could damage delicate surfaces.
For plastic