Donna...Can you send a picture of the chair so we can see the design? Thanks
What is the chair covered with? A photo would be very helpful.
It depends on the type of material and degree of weathering. In general, clean with white vinegar. Then you can paint and revive it. Of course, any repairs that are needed will be done after cleaning and will require a second clean.
If it is wood, you can either sand it down and either paint or stain it then seal it using exterior polyurethane.