>>4483340
To the shop. Buy a new camera. Keep the cum off of the next one.

D850? The top panel comes off with a few screws and that wheel is in it, remove top panel, rinse with alcohol, work a bunch of times to get the stuff out, re-assembly, good as new.

You can probably get away without removing the top panel if you use alcohol on a toothbrush, turn the camera lens facing up so it drains and brush it off.

>>4483347
It's a d7500, seems a little more complicated than just a few screws.

>>4483351

Every single Nikon made since the 1950s is built the same way, the top part is a separate assembly that comes off.

If it's anything like my Df, D4 and D800, etc., which it should be, there will be two screws above the lens mount, usually one or two on the upper sides, a couple near the viewfinder, gently pull up on it and bob's your uncle. There's going to be a couple small ribbon cables so shimmy it up when you pull it off, go by the sides.

https://www.youtube.com/watch?v=u_r3ugF7M6o

This guy can help you. But honestly, you can probably clean that without removing the top if that's the only ingress, turn it upside down so it drains and brush it off with a toothbrush.

>>4483343
You should see a doctor anon

>>4483355
The video shows you have to remove the back section before the top section comes off.

So far I've used some alcohol and water to clean it. When I slipped in the mud I didn't use the dial at all after so it didn't get all mucked up. I don't rally trust myself with opening this up, I might take it to a shop. Or I'll keep cleaning, I might be able to let it dry a bit and blow it out.