To restore an old porcelain sign, use a damp cloth to clean the surface, and remove rust by applying a paste made from 1 tablespoon of cream of tartar and five drops of water with a brush. Rinse off the paste, dry the sign, and touch up any damaged paint.
Blend the new paint with the existing paint using a dry brush. Alternatively, use a wood scraper to scrape off all the old paint, and repaint the entire sign.
To restore an old wooden sign, use a soft cloth dipped in a mixture of two drops of additive-free laundry detergent added to 1 gallon of warm water to wipe off dirt and dust. Allow the sign to dry, and then paint any areas that are faded. Run a dry brush through the new paint to blend it with the old, allowing the piece to keep its vintage look.
Wipe the sign down using furniture oil. Apply just enough furniture oil to penetrate the wood, and wipe off any excess. Once the oil soaks into the wood, spray the sign with non-yellowing polyurethane spray to seal in the oil.
To restore a gilded sign, use a small paintbrush to apply oil-size adhesive to the damaged area, allowing it to dry until it is tacky. Brush on gold leaf, and allow the leaf time to dry completely before spraying it with non-yellowing clear polyurethane.