Interesting question that often does not get much attention. My first suggestion is search the web and buy some good reference books or websites that sell Army manuals. Daryll Lynn's books are super reference and there are many others out there. A couple manuals that deal with US military grenades, say one WWII era and one more modern will fill a lot of gaps. Read them and become familiar with what is out there and what to expect before you acquire items. If you go to gun shows you will see a lot of grendes on tables but many of them are "fake" in that they are improper mixtures of bodies and fuzes or repainted practice grenades sold as fragmentation grenades. If the guy offers you a "very rare" grenade for $10 it is probably not rare and worth about $2. I would advise not buying from on-line auctions until you research the grenade being sold to ensure it is what they say it is. If you have questions, ask them on this website. The only dumb question is the one you never ask. Familiarize yourself with the rules and restrictions on shipping inert grenade bodies and fuzes around before you really find yourself in a potential bind. Decide what your interests are, if you can, and start a collection in that area. That is US grenades only, fragmentation grenades only, etc. If you have a general interest, then go for it. There are a lot of collectors, some not to far from you, who I would imagine have some spares and dupes laying around that would make nice starter grenades and would be relatively inexpensive. There are two philosophies out there on collecting. One is to save your money and buy only those hard to find grenades and build a colleciton of them. That means that the average collector will have a very small collection of really good items and that makes some happy. Don't plan on starting off with a Beano or a MK I very cheaply though! The other approach is to pick up anything you can and build a collection of reference items, slowly working your way into the "big boys" as you move into collecting. Always ensure the grenade you acquire is inert, both the grenade itself and the fuze. A grenade detonator can do a lot of damage to the body. If you have other people under your roof, make sure they are comfortable with your acquisitions. No sense in starting a war with an inert grenade! Visit other collectors if possible and see what they have and share their knowledge. Take notes and take photos. No matter who the collector is or what their background, we all started with a zero knowledge base at some point and went from there. Unless you want some people dropping in that you may not want to be there, don't advertise to far and wide that you collect ordnance. It does tend to excite neighbors and the local police to think there is a radical psycho living in town. I say that only because to many an average citizen, anyone with an interest in ordnance must be part of the fringe element and their house is going to blow up any moment. It is an interesting hobby, but although it is a relatively small community, for the most part ordnance collectors are the cream of the crop when it comes to honesty, ands a willingness to share their knowledge and collections with others. Go for it and have fun!! Bob