a lot of the guys here are being a bit stupid when they say to keep the skis. ive been through this situation before. he's saying he doesn't want any of the stuff you gave him because he needs to get you out of his mind. He doesn't want to get hung up on you. He's also trying to make a point (whether its mature or not is irrelevant): "Nothing matters to me as much as you, not even these skis and skiing is my life etc etc etc".
My advice? Drop them off at his place, if possible when he's not home. Call his mum and get her to take them. I certainly wouldn't sell them or give them away. Its just going to make him feel shit.
The best way for him to get over you is to feel good about himself. Explain to him that you want him to enjoy his life and that it will help him to take the skis back. Tell him you gave him those skis in good faith and that you'd really appreciate it if he used them and enjoyed them.