Use a large sheet of cardboard or poster board and roll into a cylinder that will fit around your child. Cut out holes for the arms, and glue felt straps inside the top to fit over the shoulders.
Cover the trash can with light gray felt or tin foil. If using felt, cut long strips of felt and glue around the top edge to make the horizontal ridges. If using tin foil make the trash can lines with hot glue, let it dry, and press and glue the tin foil over it to create the lines.
For the lid and final touches:
Cut a circle of cardboard that's as wide as the trash can. Cut and glue a lip around the outer edge of the circle. Cover in light gray felt or tin foil.
Twist a couple gray pipe cleaners together and bend into the handle shape. Hot glue to the center of the lid.
Glue an elastic band on the under side of the lid to wear it under the chin with the lid on top of the head.
Glue crumpled up paper and any funny trash items around the top edge of the trash can!