Others have already suggested the heat gun. BE VERY CAREFUL using only the minimum heat necessary. You will then need some kind of solvent to remove the remaining glue but not damage the paint. WD-40 comes to mind as well as Goo Gone or some other similar product.
I ordered some custom ones from this place, color was off so I ended up using standard vans like your old ones. However if you can get the color right you can make some really good ones here. The site didn't work well with my I pad I'd say if you order here use a Microsoft based computer and it'll probably work out ok.
If you have some of that green paint, you can mix in abrasive and spray that area with color matched non slip surface.
When I had my RV-4 painted, we used abrasive material mixed with paint and sprayed on. It was color matched and looked new after years and 600 hours when I sold it. I forgot what material he used or how he applied it. The plane was white and the abrasive was white. It never got dirty or wore off. May be something like Skid Tex (silica sand) below. There are premixed marine non-slip paint in different colors.