Fox 34 forks need a 26mm socket to remove the air cap. A normal socket will typically have a taper at the bottom which needs to be ground off to give it a flat bottom so it will properly engage with the air cap. Even so, the metal sockets and tools often mark the now ubiquitous black aluminium air caps. It ends up looking like some ham-fisted git has done a mechanical hatchet job on your fork.
For this reason, I decided to machine up my own air cap sockets out of UHMWPE. They will not mark the air cap or crowns. They are, however, not as strong as a metal socket, so you'll need to use a proper socket to reach the 24.8Nm torque on the air cap which Fox recommend.