Sold a baby item - had finished with it a couple of months ago, washed it and put it away, so when I sold it, and posted it, it was still ok and IMO didn't need washing before posting.
The buyer's left neutral feedback "I had to wash the item, although I would always wash items before using them" 
I know I'm just going to have to get over it, but I'm a bit annoyed and wanted to vent!