2 x Single Duvet Covers - Old condition is fine (Kenilworth CV8)

Looking to wrap 2 chairs for storage and single duvet covers would be perfect for the job (so the chairs are free from dust and can still “breathe” and not go mouldy/damp) - it seems wasteful to buy 2 new covers for this if there might be used ones too good to be thrown away but not quite good enough for charity etc