Remove the tin ceiling panels with a pry bar. Gently pry the tiles off of ceiling. Do not bend the tin. Take the nails out with the panels; do not attempt to force the tin off the nails or you will rip it.
Test the tin for lead paint with a test kit. If the ceiling tiles were painted prior to 1978 or you aren't sure of the age of the paint, test the tiles before you begin working with them. Removing lead paint presents a serious health hazard. If the kit produces a positive result, contact a professional for advice. In some cases, lead paint can be sealed over with fresh paint, but you should not attempt this until you get professional advice.
Remove any existing paint with a paint stripper. Apply the paint stripper and let it set for a few minutes. Begin scraping off the paint gently. Do not scratch the surface of the tin. Use a toothbrush to get into detail areas.
Burnish the surface of the tin with a soft cloth. Rub in a circular motion to clean off any remaining surface dirt and debris.
Re-hang the tiles on the ceiling with a hammer and nails. You can use the old nail holes as a guide in finding the ceiling studs. Nail up one panel at a time. Overlap the seams slightly to avoid having visible seams.