This isn’t a cheat, I promise. I sent off a massive box of goodies to a friend the other day, and it contained the following:
Yes, those are jars of fabric!
This packing technique can be traced back to my childhood excursions to sleep away camp (I did grow up American, remember). My mum would send tins of chocolate chip cookies or brownies (see, properly American) and the best way to get the tins home in your suitcase again was to fill them with socks.