I've been to DC twice in my life, once on a middle school honor roll trip, and again on a solo trip just over two years ago. I remember panhandlers EVERYWHERE on the first trip. They lined the national mall, most of them shaking cups with change. I only encountered handful of them on my second trip. One lady just kept repeating "penny for a sandwich?" to passersby. I responded "Lady, if sandwiches cost a penny here, I'm moving!" I didn't give her anything. I did give some pocket change to a beggar in a wheelchair, but only because my phone was brand new and I didn't want the coins to scratch it.