My little girl does, too. She was being such a ham for our photo shoot.
Here's what I did:
Step One: Dismantled the chair- removed the tray, tray arms and seat belts.
Step Two: Tried to remove the previous polyurethane coat by hand sanding.
Step Three: Used stripper to remove the polyurethane. I didn't use the stripper at first because I personally don't like having to clean up all of the gunk it leaves behind. But it worked.
Step Four: Still had to sand parts down until the wood was back to its original form.
Step Five: Cleaned the sand off and applied three coats of walnut stain. In between each coat, I waited the appropriate amount of dry time according to the back of my can of stain. (At this point in the process I also stained the top of the high chair's tray)
Step Six: Waited 24 hours and then applied first coat of polyurethane.
Step Seven: After first coat dried, I lightly sanded each piece and then applied another coat of polyurethane.
Step Eight: Created a flower pattern out of clear contact paper, attached it to the high chair tray and then spray painted three coats of spray paint.
Step Nine: Removed contact paper when paint was still slight wet.
Step Ten: Roughed up the edges of the tray to give it a "weathered" feel.
Step Eleven: Put everything back together!