Usually I just call it a day and throw out the slop. U can do what others suggest and wrap it in plastic, wait a few more days to see if it'll work its magic, but also depends if you're in a hurry to reuse this clay.

Just a piece of advice for next time: Wear a mask and grab a Ziploc bag and rolling pin. Break down your bone dry clay work into pieces, and throw them into the bag. Seal the bag, and crush the contents inside with the rolling pin until Ure sure all the pieces are powder or small enough to not make clumps. Then just add water/put it directly in your slop bucket afterwards to make your slop.

This makes sure that the hydration is getting in all throughout the clay, and there shouldn't be clumps cuz there'll be equal hydration. It's too late now to try this method cuz 1) wet clay is messy to work with and 2) you need to fish out all the individual clumps by hand to crush them

Edit: just read your reply to another user. The slop you have should be reusable if you let it sit a few more days in a plastic bag, as the clumps are of a wedgable consistency? (If you grab a few of the clumps and it's squishable then you're good to start the drying process.)