Can someone find me ways to make my money/stamp collection into legit extracurricular

<p>I am currently junior now and my parents and I collected copious amount of stamps, paper money and coins for around 15 years. I spent a lot of money on this stuff and heard that these type of odd collection can also be somehow extracurricular if I can prove this. Can someone tell me how can I make this collection a legit extracurricular that can be written and considered very special for college application? Is blogging a blog about foreign currency collection and stamp can be considered as extracurricular too?
Thanks</p>