I remember in high school rusting out a set of brand new Vokeys and the look my dad - who paid for them - gave me when he saw what I’d done. He asked why and my best response then was, “Cuz it’s what the good golfers do and zippity spin padre!”
To be honest, I love the look of a rusted out wedge, but if someone were to ask me what the benefit is I don’t think I could tell them. From what I’ve read, aside from no more glare, there doesn’t seem to be any real tangible benefit.
What do you think?
I was all about the look back in HS/university, now it’s very much not me. I want my wedges to look as new as they can for as long as they can. On the performance, seems like testing is at best inconclusive or at worst, the rusty wedges spin significantly less than the non-rusty counterpart.
The metals used in wedges today for use with current golf balls can create so much more spin than rust. Now, if you’re going to play a balata ball, it’s a whole different story. 
I love the raw wedges that rust over time. I am not a believer that they increase backspin but do like the looks of them.
I found a balata ball the other day and played it from 95 with my sandwedge. There was hardly any ball left it was so shredded. Spun the hell out of it, though.
Nay on rust
Found an old grove wedge a few months ago and took it out for a spin, literally.
If it was uniform rust on the face of the club, wouldn’t it be a bit like sandpaper, maybe spinning the ball more? But it would make the grooves ineffective, wouldn’t it?
I, too, like the look and feel of a brand new wedge. Plus, if rust helped the spin rate, don’t you think you’d see all kinds of old, rusted wedges on the tour instead of the brand spanking new ones that they trade out every couple of weeks?
Still a couple of players out there who intentionally rust out their wedges although it seems much more out of fashion than it used to be. The trading out is all about the grooves. Pros practice their wedges much more than amateurs, so where as we might get 100 rounds or so out of a wedge before there would be any noticeable performance difference, the pros will put that kind of wear on the grooves in a couple months.
I absolutely love the look of a rusted out wedge. The new Cleveland RTX ZipCore wedges in Tour Rack finish are coming to my bag very soon.