grain storage and plastic: what is acceptable?

[Bill]

would you store grain in buckets like the orange ones from Home Depot? What types of plastics are acceptable for storing my grains? I already got 2 of the blue containers for my 2 row sacks which I know are food grade, but they are too large for only 10 or 20 #s of grain. I need someting smaller.

What are acceptable plastics and how do I tell which is which? I tend to look at the recycle number, if that is not a good guide, let me know.