Google "Gamma Seal bucket lids" 
O-ring sealed screw on lid that snaps onto a standard 5 gallon bucket. They are required equipment on many rafting rivers to pack out human waste, they seal quite well. 
Don

Sent from my iPhone

> On Jul 30, 2014, at 7:02 PM, Alistair Bell <albell@SHAW.CA> wrote:
> 
> Better (better meaning leads hassle with lid) than a 20 joint compound pail is either an olive container with screw lid and o ring, or similar but beefier chemical container with handles and ca action clamping lid. Chemicals inside were harmless, bacterial culture media and one had poly lactide.
> 
> We have a range of sizes, from 5 litres to 50. Really great things for van camping.
> 
> Alistair
> 
> 
> 
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