waterlily, If the lumps smooth out by hand easily, you can use the cement. If the lumps are rocklike discard the bag. Cement does have a shelf life, even without the hard lumps.

How are you storing your cement? The lumps are caused by moisture in the air. Moisture will even migrate through a concrete floor to the bottom of your bag of cement. Billie

I am storing the cement in its own bag in a large plastic garbage can with a tight fitting lid. I think I may try to find smaller amounts of cement at a local cement factory. Not sure if they sell it - but it has to better than disposing of the harden lumps!

Garbage cans don't have tight-fitting lids. They may have lids that are tough to open, but they don't fit tightly. Fill it up with water and tip it... if water runs out, moist air can flow in. (Guess how I know....)

I buy a 94# bag of cement and divide it between three 5-gallon buckets with tight lids. I had to buy one of those lid openers to get them open without breaking my nails.

The link below shows what the bucket openers look like, but you can find them in hardware stores and Home Depot, Lowes, etc.

Sue

Here is a link that might be useful: Bucket opener photo

I need to get a bucket opener.

I've kept my cement in my periodically very wet basement (salamanders, weird fungi) in a Rubbermaid trashcan in a contractors' grade plastic bag for years now & it hasn't lumped up.

Steerite brand containers don't hold up at all - don't bother to buy those.