My mother always brings another suitcase to England. Not so much these days now with the Internet and so forth and her being able to get British stuff in specialty shops: but one of the things she regularly stocked up on, and I mean stocked up on to the tune of buying tons of it at a time, was greaseproof paper.
It comes in sheets, in a waxed bag - and to some it looks like art supplies - sheets of vellum-like, waxed parchment. But it's not waxy enough to be like what Americans think of when they talk of wax paper, that's a thickly waxed substrate that has a tacky surface like a wax candle. It's soft, silky, and has a very specific crinkling sound.
Although it can be used and is preferable to use where people use Saran Wrap - and I was given it to use as tracing paper when I was a small child, a task it does admirably - its quintessentially British use is to wrap sandwiches. The American style is to use plastic sandwich bags or to weap sandwiches in a cling-film, something which imparts a plastic-y taste and really has an ugly hand-feel (oh look, I'm peeling my food out of a substance used mostly in tattoo parlors to wrap fresh, bleeding tattoos). In the UK, or at least on my few visits there, you unwrap, gloriously, out of a nice, crinkly wrap you can use a pencil on - so you know which ones are ham and cheese and which ones are pickle sandwiches and so forth.
On my last visit out to her, I jokingly asked if I could have some greaseproof, and she obliged by handing me some from Boots back in the early 1990s. Its faded, yellowed-brown appearance in no way took away from its usage: I use it in baking and I also wrap my sandwiches in it, cut on the bias with either a cup of tea or a beer.
There's a lore that says that sandwiches taste better out of greaseproof paper, and maybe some boffin will eventually find some intruiging reaction of time + paper + bread we've not known about. But nevertheless I get a bit of a kick out of pulling out sandwiches and unwrapping them and having people ask me "what exactly IS that"?
I'm slowly running out of the stuff and my mother is now too old to visit Blighty, so I'm going to have to find another supply. Since amazon.co.uk won't deliver it to the US, I'm going to maybe have to get another suitcase and visit England myself, getting enough greaseproof to last me a lifetime.