Let me state up front that my reply will sound evasive. Its not intended to be that way, but it may sound that way for good reason. "here", in the willamette valley oregon, a lot of seed, mainly small seeds like grass seed and small seed legumes are raised and the seed cleaning business is an essential part of our business. Not a lot of grain is sent to cleaners "here".
Years ago, there was a.............uh..............big F up known as ABT. http://findarticles.com/p/articles/m...s_/ai_59986358
This scam/scandle, etc., struck a vital nerve with the seed growing community. Many new "backyard" cleaning facilities went up over night, and most continue to do business within the zoning laws of oregon. This is good news for the grower, but not so good news for the cleaning industry. Prices for cleaning have gone from a set, advertised price to a private quote to each individual not to be disclosed to anyone.
So,... though I cant tell you what I pay for cleaning grass, I can only give you an advertised price of about 6 cents/pound inweight. Clovers, usually needing a few extra steps, through different machines, has been advertised at 10-11 cents/pound inweight. These prices are for a brick/morter facility capable of cleaning most grains and seeds, and have large inbound storage capacity. Most of the grass cleaners are smaller, though permanent, facilites that specialize, and may even in some cases, only clean grass. These are usually farmer owned/operated facilites with very little inbound storage, and in some rare cases charge on the clean weight.
Are you thinking about putting up a cleaner?