When making scrambled eggs in my cast iron skillet, I find the eggs look "grimey" after they are cooked like the seasoning is coming off. Am I not cleaning the pan correctly? Does it need to be reseasoned (possibly better seasoned)? Or are eggs in cast iron a bad idea?
You hit the nail on the head. The seasoning is coming off. It's just chunks of fat/oil with bits of black rust, or black oxide.
The solution is to either stop using the pan to cook scrambled eggs, or strip the pan down to the cast iron and re-season it. Seasoning is a two part process. The first part is developing the layer of black rust, and the second part involves coating the pan with oil and then using heat to turn the oil into a polymer that provides a non-stick surface. If seasoned properly, you really shouldn't see any issues.
There is an interesting series here on the subject of seasoning cast iron:
I'll agree with the input provided by the other two responders - but have some additional data to add.
First off - Cast iron pans are just fine for cooking eggs. While a teflon pan will be a bit easier - a well seasoned cast iron pan is "almost" like a teflon.
Concerning your black bits: your pan is probably just "dirty" and as the previous person mentioned, needs to be cleaned - and re-seasoned. While I'm not a blacksmith - I have spent a great deal of time in kitchens.
Take your dirty pan - and put it in an oven at 400 Farenheit for an hour. This will not warp the pan - but will burn off any crap on the pan. It might make smoke ...
Take some dish soap - which normally is a bad idea for cast iron, and HOT water and clean it well. Rinse it well with HOT water.
After its dry (and possibly oxidizing .. aka RUST) ... take a paper towel and a bit of vegetable oil (NOT olive oil due to a low smoking point and high cost) and wipe it out. pour 3mm (1/8") of canola/soybean/other vegetable oil in your pan. put it in the oven on 250 Farenheit for a half hour.
What this does is allow the cast iron to expand, opening the "pores" in the metal. (ok, I'm just guessing .. but no one disputes that hot metal expands right?)
it might smoke ... but the idea here is that ... the heat "opens" up the metal, and when it cools, the oil becomes trapped in the porous surface of the cast iron.
Whether my technical explanation is correct or not .. I promise you ... based on experience:
your pan will not leave black crap in your eggs your pan will be as close to non-stick as teflon (which is hard to beat ... even with a cast iron pan) if you clean it with no soap, and don't over heat it ... will improve over time
like I said ... its hard to beat a nice teflon pan. that shit is magic. HOWEVER ... there is no reason that with the right temperature ( med-high), and the a thin coating of non-polarized (fat), that your eggs will come out like magics.
Keep in mind that fat makes everything taste better ... so there is no shame in putting some butter or oil in the pan if you have good taste. keep in mind that butter solids will brown quicker than oil ... but that won't lead to black bits.
overall --- nasa wins. a NICE teflon pan is awesome. no dispute there. calphalon is sweet too. HOWEVER .. I'd much rather use an old cast iron pan than be re-seasoned, rather than a crap "non stick" pan.
Another advantage of cast iron pans - is that because they are heavy (aka have mass) ... they distribute the heat more evenly than a cheap aluminum pan coated with space rocks (teflon), especially with a lame ass electric element with hotspots.
bottom line .. a well seasoned cast iron pan is fine. a teflon/calphalon pan might be easier for a rookie trying to cook eggs, or using "less fat"
While the other answer is correct, I have had good experience with cleaning my pans by heating them up a bit on the stove and carefully wiping it down with a damp rag. It doesn't remove too much seasoning and keeps the food a bit cleaner.
The pan will be reseasoned every time you cook with oil so as long as you use the pan once every couple days it will be fine. If you are unsure then just rub a bit of oil into it after you wipe it with the damp rag.