These will look great with neon back on them. The "F" is a little over 3 feet tall, as shown the set is approximately 16' long. Each letter still has it's original stand, you never find them with these anymore. Stands can be removed if you wish to hang them on the wall. All I've done is wipe the faces down with Windex, see photos for condition.
The black on the "n" appears to be dried tar. I'll be happy to store this sign right where you see it for no charge for up to 6 months. I'd guess you'd be looking at a few hundred with crating. The item "Vintage ORIGINAL PORCELAIN Large FIRESTONE NEON Letters Sign OLD Tire GAS Oil" is in sale since Thursday, April 18, 2019. This item is in the category "Collectibles\Advertising\Merchandise & Memorabilia\Signs\Original\1930-69".
The seller is "antique_illumination" and is located in Indianola, Iowa. This item can't be shipped, the buyer must pick up the item.