When you buy a new baseball glove, it will typically be much too stiff to open and close comfortably, especially for a child. It will need to be broken in.
To “break in” a glove means to do two things: One, to soften the leather just enough that you can open and close it, and, two, to shape it so that it naturally forms a pocket to hold a baseball.
First, you’ll want to make sure you have a glove that fits well. If it’s too long or too short for your fingers, if you can’t get your hand into it or it slips right off your hand, breaking it in will not solve those problems. So you want a new glove that fits properly (aside from feeling awkward on your hand in the sense that it’s too stiff when new).
There are many ways to break in a baseball glove. The problem is, some will potentially damage your glove. It might be OK to risk those methods with a cheap glove, but not an expensive one. But here are some of the methods that people have used:
1. When you get right down to it, there’s one tried and true method of breaking in a baseball glove, which also happens to be the safest and thus most “correct” method. That is simply to use the glove.
The only disadvantage to this is it takes time, and people are impatient, but really it’s the best way to go. Play catch for enough hours (or catch a ball off the wall, go to a batting cage and catch the pitched balls rather than hitting them, throw the ball into your glove repeatedly yourself, etc.) and gradually the glove will loosen up and form a pocket. Every time you let the ball strike the “sweet spot” of the glove where you want to catch it, especially if it lands in there hard, you’re taking another tiny step in the direction of breaking it in. It’s just a matter of repetition.
2. The next best method is to place a ball in the glove and then tie the glove up so that it’s gripping the ball in its pocket. To really press it tight around the ball you can put additional weight on it, for instance by putting it under your mattress with the ball in it when you sleep.
These two methods can be used in conjunction with each other. Play catch with the stiff new glove during the day, and then wrap it up with a ball in it at night.
3. Other methods are more controversial and, again, there’s typically no reason to risk them unless for some reason you “have to” loosen up your glove quickly and can’t break it in gradually by using it.
Generally these involve rubbing the glove down with something to soften it. There are specific baseball glove leather oils made for this purpose that you can buy wherever you bought your glove. Other substances that people have used with success include Vaseline, foam shaving cream, and saddle soap.
If you do use one of these, remember that too little is better than too much. Don’t slather it all over the leather; use it sparingly if at all.
Heat will also soften up a leather glove, but that risks damaging it even more. Some folks leave a new glove out in the hot sun. Others take it to the extreme of baking it in the oven, or even in a microwave. Try this at your own risk; what you might well end up with is a glove so limp as to be useless.
But to reiterate, to break in your glove properly, nothing beats catching a ball with it repeatedly.