Alright kiddo, so you know how the military has a lot of equipment and supplies like uniforms, tents, and guns, right? Well, sometimes they have too much of this stuff and they don't need it all anymore.
So, the Military Surplus Act (also called the Kahn-Wadsworth Act) is a law that was passed a long time ago to help get rid of all the extra stuff the military has. The law says that the military can sell their extra equipment and supplies to people or organizations that need it, like other parts of the government, schools, or even regular people like you and me!
The cool thing is that since the military already paid for all this stuff, they can sell it for pretty cheap. This helps them get some money back for the things they don't need while also helping out other people and organizations. It's like having a big garage sale, but instead of selling used toys and clothes, the military is selling their used equipment and supplies!