Preserving Autographs on the outside of a book

[il0veseamushp]

I had someone ask me the following question..

do you have any tips on how to preserve an autograph that is on a Harry Potter hardcover book on the very front cover? (not the inside) I REALLY know it's going to fade and i want to preserve it as long as i can. any tips?

i really dont know how to answer so i thought id ask here specially since i have more or less the same quest since i have 2 autographs on harry potter character wand boxes that i want to keep on the boxes as long as possible. at the moment i have the boxes in plastic/ziplock bags to keep the dust and anything in that matter of fact away from the ink.

any tips?