I cannot seem to get all the rust off of my cast iron pan. Any tips?

Scrub it down as much as you down, dry it off and season it. It'll go away. For seasoning, what I usually do is add a table spoon of oil, and rub it down with a clean towel or paper towel, both inside and on the outside and throw it the oven at 400 for about half an hour, if you have plastic handle, you can wrap it with a damp paper towel and wrap that with aluminium foil, if you can't remember what temperature it's rated for. I do that two-three more times, i take it out of the oven while it's still hot, use a paper towel to dry off any oil that may not have gotten a chance to polymerize and repeat the seasoning process.

tl;dr wash/scrub, dry, season. it'll go away. cast iron is very forgiving in that sense.

/r/Cooking Thread