I store my grains and equipment in an empty bedroom upstairs. I have a 50# bag of 2 row with maybe 15 # out of it with the top rolled down. I just went up to grab some malt to do a brew and there is mouse crap on the top of the grain and some has been eaten. NO IDEA how a mouse got in it as there are no holes and the top is rolled down pretty tight. ANYWAY would you just toss the whole bag or take a good layer off of the top and use what is underneath..... wife says pitch it and go buy more ( I agree) BUT I just bought a 40 dollar pump and hoses for brewing today.