Q: iPhone is linked with old apple id

hello, i have an old iPhone 4s and i suddenly found it and i want to use it again, but it is linked with a very old apple id which i forgot, i tried clicking on the forgot my apple id thing but they asked for the email and i naturally don't remember which email i used, and now its locked and i should log in with that old apple id, i tried to erase everything on it (i don't know the word) but it didn't work still, please help.