So how the fuck do I clean these cast iron pans?

Steel also bacon grease works good too

sandblast them

Not the OP.

I dont own any iron cast, for now at least.

But if I buy a used one and want to get rid off all tha unknownfrom grease. Why souldnt I use soap? I get it for the steel wool. But why sot soap if I want to get it clean before season it myself?

There's no reason not to use soap, especially if you plan on re-seasoning it.

Some people have a wierd mental hangup which makes them think that soap will ruin the seasoning on a pan. Assuming the seasoning was done correctly then a quick scrub with soap and water won't hurt it. Granted you wouldn't want to leave it soaking in soap water for days, nor would you want to stick it in the dishwasher. But the pan seasoning is much more durable than some people think. A basic wash with soap and water won't hurt it at all.

Thanks for the response coo/ck/

Want to really get rid of it built up grease the easy way? Put the pan in a cold oven that has cleaning option, turn on the exhaust fan and fire it up, everything on that pan will fall off as ash, unless its rust. You could also get some oven cleaner spray and spray up the pan with it and put it in a plastic bag to let it work for 24hrs, then rinse off. You'll have to reseason the pan though after this. Does the pan have any signs of rust or damage from rust? The oven cleaning setting method though creates a bit of smoke.

I just clean mine with water, a little bit of soap, and a scrub sponge like any other pan. If it needs to be re-seasoned, I re-season it.

Blast it with piss

This.

Many times people will leave grease or oil in them to preserve them for long term storage.

Just make sure you dry it thoroughly

Seconding this, sand is commonly used to clean cast-iron cookware.

will putting cold water into a hot cast iron pan warp it, or will that only happen with teflon or stainless steel?

soap and water

Just use soap and water, then immediately dry it completely. Don't listen to the autists.

I wouldn't risk it. You don't have to let your pan cool down all the way before washing, but at least wait a few minutes.

Soap, water, and a soft-bristled brush, nothing more.
If it's a hand-me-down, I'd want to keep that seasoning on it unless it's absolutely necessary to redo it.

Just rinse with water, and wipe with a napkin. Sometimes I'll wipe it with a couple drops of oil if it starts looking dry.

I can't believe how non-stick it is. From day one even when it was factory pre-seasoned, eggs just slid around it like they were floating. Now thats its properly seasoned, absolutely nothing sticks to it. I'd have to purposefully burn stuff to make it stick, and even then, it eventually comes off without much fuss.

Iron doesn't suffer from thermal expansion or contraction in the same way that other metals do. It also has a decently high stress point, and is designed by nature to take a beating. If you don't want to risk it, don't. It shouldn't hurt it, though. (You could totally fuck your seasoning, though).

I bought a cast iron fry pan from kmart today, is it going to be shit quality?

It's true that "they don't make them like they used to," but modern cheap cast iron cookware can still last a lifetime with proper care. They usually come pre-seasoned, but if that's not enough (it isn't) then you can add a few layers of seasoning yourself. The pan will have a bumpy textured surface, which if properly seasoned shouldn't affect sticking.

tl;dr you're fine

Little vinegar, little baking soda. Spread it around with an old brush, let sit for fifteen minutes. Wipe off, rinse, wipe off again. Put it on heat to dry up any residual water and then apply flaxseed oil all over.

it wasn't preseasoned, it cost me $9 so I'm not worried if it sucks, I'm hoping I can make it last a long time