Hey there RoyalGorillaxx, Cardboard is totally fine and actually perfect. In fact you dont need to use your grow box at all. One of the best dries i've done is using a cardboard box. Make two hole and pass string through it, then hang them. Close the box and just leave it at room temperature (no need for air holes, etc) for two weeks. If you have a bigger box you can make a bigger hole for a small fan you can use as an extractor but i find the dry is usually a bit too quick like that. The main advantage of having a fan on the dry box is to reduce the likelihood that there might be mold. So just keep that in mind. Remember, drying is the most important part of a grow. Hope this helps ! 🚀