What's the best way to soften caked brown sugar?

Play it a Celine Dion record?

If it was me I would wrap it in a tea towel and let it drop from 5 feet.
Just for the kick of it.

Microwave Here’s the lowdown or if you a have couple of days before you are going to use it; slices of bread or apples slices.

@Tropical_Willie Thanks. Baking today. Will try the microwave.

A friend makes clay discs to moisten & place in the bag.
I don’t know if they work but I’d probably try the microwave with a little bit of water.

@lucillelucillelucille I had one of those a while ago. It did help.

I had used half of an apple earlier but his does work but the apple turn mushy and brown so that should be discarded .
I used the clay disk and that works as I keep it in the package always .

I always used to keep it in an air-tight glass jar, and it stayed soft. Haven’t baked much lately, but it might be time again. I do love fresh oatmeal cookies.

This is what the Food Network suggests. Before we had microwaves, my Mom always put hers in the oven with a damp towel & allowed it to heat up some. I don’t know what temp she used & she’s no longer with us for me to ask, so I’m guessing 325 F as anything hotter would ruin it & anything cooler wouldn’t dry the towel fast enough to help. If you decide to use the microwave, I suggest going half power to keep from ruining it.

Microwave. I have brown sugar that is 3 years old and still soft. It’s in a plastic tie bag, and then inside of one of those canisters that clamps down. I highly recommend this method for storing brown sugar. My canisters look like this, I don’t remember where I bought them. https://www.homedepot.com/pep/Home-Basics-Stainless-Steel-Canister-Set-4-Piece-CS10067/300171141?mtc=Shopping-BA-F_HDH-G-D29B-29_29_HOUSEWARES-MULTI-NA-Feed-PLA-NA-NA-Bakeware&cm_mmc=Shopping-BA-F_HDH-G-D29B-29_29_HOUSEWARES-MULTI-NA-Feed-PLA-NA-NA-Bakeware-71700000053156037-58700005102355548-92700046592912032&gclid=EAIaIQobChMIssjSwbqs6AIVd4FaBR0lcQvHEAQYBCABEgJSG_D_BwE&gclsrc=aw.ds

Mine have a silicone ring inside the top so it is very airtight.

How did the cookies turn out?

Great! at least the one I ate did. The rest went to neighbors…...

My Mom always put a piece of bread in with the brown sugar.

The microwave method that @Tropical_Willie linked to was pretty effective, but I had to do it about four times and scrape between. It was a large brick.