I know it sounds stupid but i've done it and it works. Plus, it's good for their hygeine .buy some small animal shampoo and and put them both in the bathtub soak them with the shampoo and rub them together. (Don't get in the eyes, ears, or nose) they will be VERY scared but they will bond over the scary momentand when you put them in the cage they will smell the same so they won't fight and by the time the shampoo smell wears off they will have already gotten used to each other