Dexter-Russell 16090 S242½PCP Traditional™ Pancake Turner, 4" x 2-1/2" Solid Stainless Steel Offset Blade with Ergonomic Rosewood Handle, USA-Made Professional, Perfect Cutlery Packaging

> Do not use soap

Using modern dish soap on cast iron is entirely fine, the detergents used are much softer than the sorts of lye-based soap that this advice stems from, and will not remove the baked-on (polymerized) seasoning. (It will slightly slow down the rate of seasoning accumulation by removing the thin layer of unpolymerized oil, but this can be fixed by just wiping on a thin coat of oil after washing and drying the pan. I usually don't even bother doing that much though.)

In general I think that most guidance for using cast iron is overly cautious and makes it sound like more of a hassle than it needs to be. At the end of the day it's a large hunk of metal, and there's very little you can do in the kitchen that will permanently mess it up.

edit: One piece of advice I do have: don't use a plastic spatula, they're a suboptimal choice people are forced into by easily-damaged cookware. Since that's not a concern with cast iron, you should get a thin metal spatula (example: https://www.amazon.com/dp/B0015R7P6O). The tip will always be exceedingly thin and never deform/melt/get torn up like a plastic spatula, and as a bonus it doubles as a very effective scraper for easy cleanup.