I purchased a lodge cast iron skillet 4 years ago. It came seasoned but I scratched everything off and seasoned it every now and then (probably 10 times over a year) in the oven. I also used it mostly to cook greasy things like bacon. After every use, I would also do a "light" seasoning by warming the skillet on the stove, put some vegetable oil on it and rub it away with a paper towel to make a very thin coat.
The past two years or so I stopped seasoning it because it started to have some non-stick qualities, but it still left some residue after each cooking that I had to clean up either by pouring hot water on it while it was hot and then rubbing it off with my wooden spatula, or just wiping it with paper towel and sometimes with a bit of salt.
But I was under the impression that after all this use, it'll turn better than the nonstick pans out there, that I can fry eggs on it. I don't dare do such a thing right now because the cleanup will be a mess.
What can I do to improve its nonstick quality?