Let your cornbread cool down until it reaches room temperature. 

Once it has cooled down to room temperature, cover them with plastic wrappers. Make sure that there will be no air sneaking inside and no buildup of moisture will take place. 

Take it out of the wrapper then place it on either a plate or a baking sheet.

Then put it in the microwave or the oven for about ten to fifteen minutes. After that, slide them into the fridge.