While pure gold is forever, gold plating often fades with the passage of time. Thankfully, items that are gold plated can often be repaired and restored to their former glory. While you may not always be able to restore them to look as good as new, you will be able to make the gold plated items look much better than they did before restoration.
Clean the item. Prepare the surface and remove all contaminants that could cause problems later. Use a gentle hand soap and a tooth brush to remove any dirt and grime. Pat dry using a paper towel, then let the item air dray completely to make sure that the surfaces, including any crevices, are free of moisture.
Buff the surface with a jeweller's cloth. Sometimes, this is all that is needed to restore a uniform lustre to the surface and to dull down the high points where the underlying metal shows through the gold finish. Jeweller's cloths are often made to wipe tarnish off of silver, but they are also effective on gold plated items.
Use a gold plating kit. If cleaning and buffing did not provide a satisfactory result, there are kits available that are aimed at helping people restore gold plated items.
For immersion gold plating kits, put the item that needs plating repair in a small basket, which comes in the kit. Place the basket on an activator disc. Next, you place the basket and activator disc into a preheated gold solution (which comes in the kit as well).
After several seconds, rinse the object in water, then buff it with a polishing cloth. It creates a gold bond in seconds, which serves as an easy fix.
Visit a local jeweller if your piece is of extreme value as the jeweller may have more advanced techniques such as electroplating which can be used.