Extra Large Jelly Bag

Sadly, I've had to discard my grandmother's jelly bag made from (would you believe) a woollen blanket!  It was falling apart, so I now need to make/acquire a new one.  Having researched online, I can't seem to find one as big.  Does anyone know where I can purchase one?  I know I could make another from a large piece of muslin (doubled or trebled), but the smaller ones I've made always stain and I'd like one that would be more resiliant too.  Any ideas gratefully received!   

Pillow case or a piece of fine net curtain?

My local fabric shop sells very,very fine nylon mesh by the metre ( its about 1.25m wide). It looked as fine as those Tala jelly bags on sale