I spilled used cooking oil in my kitchen pantry floor. I used the flour method to successfully clean it up, but now the floor on the other side of the wall has a pretty loud creak when walking on it. Can you please help?
It might happen that the floor was not installed correctly - i.e., without some "free" margins to allow for some expansion.
It might have happened that the floor absorbed some grease (maybe even water during cleaning) and expanded on this side. Because there are no margins, this expansion pushed the floor on the other side, curving it (slightly) upwards. So now, when you walk over the "bump", it squeaks.
In this case, the only good solution is to hire a specialist to re-do your floor. If he is an "artist" and he has specialized tools, he might be able to fix it even without removing everything and then re-applying - he would just create the "margin".