You used too much oil

You used too much oil.

Yes, that’s almost certainly the issue.

Seasoning needs a thin layer of oil. When you use too much, it pools and polymerizes unevenly, turning into that patchy grey mess instead of a smooth black finish. Think of it like painting a wall — one thick coat looks terrible, a few thin coats look great.

The fix is to scrub off that gummy layer (steel wool and dish soap, or oven cleaner if it’s really bad), then start over. Wipe the oil on like you’re trying to remove it — barely a sheen. Then bake at 450°F for an hour.

A common pitfall: following videos that show people glistening their pans with oil. Ignore that. Your pan should look dry going into the oven.

Future you deserves a pan that actually works, not a science experiment.