In a small bowl, dissolve gelatin in boiling water. Refrigerate until partially set, about 1-1/2 hours. In a bowl, combine wafer crumbs and butter; press into a 13-in. x 9-in. dish. Set aside.
Beat gelatin with an electric mixer until foamy. Add the lime and lemon juices. Gradually add sugar, beating until dissolved. While beating, slowly add the milk; mix well. Pour over prepared crust. Refrigerate until set. Garnish with Pots o' Gold if desired.