Hmm, I've never run into this myself, but it comes to mind that smacking it a bunch with a hammer might work. If that doesn't, I'd just go and get more (perhaps in a smaller quantity).
If you are using it for cleaning, you generally will make it into a paste, so it doesn't really have to be a powder again. I would try to chip away at your baking soda rock. In the future, avoid getting any moisture into your baking soda. That is probably what caused your problem.
I want to use it with vinegar to clean the drains and a paste isn't possible. Think I will just throw it out and get a smaller bag. Thanks
Just add the vinegar to a few lumps you smashed
I had the same problem...I need it for my goats, for cleaning, etc. It got hard as a rock even before I opened it. I just tried this, and it works. Take a pastry blender...the kind with a handle and metal splines....just scrap the top of the "rock", and it turns into powder again.
Put a quarter of an apple inside the box and let it sit there for a day or two, the moisture from the apple should help it soften up a little bit, much like brown sugar.
(1) Remove the baking soda from the box. (2) Place the baking soda in a microwavable bowl. (3) Cover it with a napkin or paper towel. (4) Microwave for 1 minute. You should be able to scrape it with a spoon by now. (5) Microwave again for 1 more minutes. (6) Put the baking soda in a Ziploc bag, and gently squeeze the bag. The baking soda should return to its normal form.
I SHAVED IT WITH THE COURSER SIDE OF A BOX GRATER. It was actually kind of fun to do and went pretty fast! You can hold it up with hand on top and grate it on the side like you would cheese... or you can put it down flat, hold the end handle with one hand and grate the soda horizontally, away from you. No mess either. Pretty easy to clean up.