Natural, NON flame retardant stuffing for nursing pillow?

I've just made my own nursing pillow (since Boppy pillow seem to be around the £50 mark!) and I'm looking for a nice natural filling to stuff it with. I have polyester filling but that appears to be full of flame retardant chemicals.
I have thought about using cotton (cotton wool from Superdrug??) or natural wool fleece but I wouldn't know where to get these, also, how would they fair in the wash. I also thought about using Buckwheat husks but that would cost me at least £25 for the filling alone. My sister suggested lentils but they might be dusty and would probably be very heavy.
Any suggestions?

Just out of interest, here's a photo of my pillow slip cover that I made yesterday.

What about bean bag beans? I don't know if they'd be flame retardant though, they might well be.

What about buying a cushion or pillow and then taking the stuffing out? I don't think there are many natural fillings which are washable though, feathers and wool etc clump when washed. You'll probably be better making a slip cover to go over the top which can be washed.

What about buying a cushion or pillow and then taking the stuffing out? I don't think there are many natural fillings which are washable though, feathers and wool etc clump when washed. You'll probably be better making a slip cover to go over the top which can be washed.

I have made a slip cover (pictured) the cushion itself is just made from a cream cotton sheet. It would be nice if the whole thing could be washable (we had much baby sick and spraying milk end up on the bolster cushion I used with my ds) but I know what you mean about washing... Maybe I could add a layer of lanolised wool between the cushion and the cover....?

Or maybe a fleece or minkee layer?

If you think wool might work (and wool is naturally flame retardant) you could try here http://www.winghamwoolwork.co.uk/fbr_wol_white.php
http://www.winghamwoolwork.co.uk/fbr_wol_coloured.php

some of the wools on those pages are £1.50 per 100g, they had stuffing wool cheaper but seem to have sold out. Wool needs to be stuffed very firmly to help it keep it's shape, so you'd need lots of it. I've never washed my BFing cushion, just the outer covers and its always been fine, the odd bit of surface cleaning when necessary.