Lets say one has wants to cook fleishig food in a fleishig pot on top of a gas stove top. The gas stove top was recently used to cook milchig food in a milchig pot, and some residue of the milchig food spilled. Now, there is no milchig residue on the part of the stove top grate upon which the fleishig pot will be placed. However, what would be the din if there is milchig residue on the bottom part of the stove top grate that is not in direct contact with the fleishig pot. Would one be allowed to cook fleishig food in a fleishig pot on this particular grate. Additionally, what would the din be if there is no milchig residue at all on the stove top grate, however, there is milchig residue on the stove top itself? In that case, would one be allowed to cook fleishig food in a fleishig pot on this grate?
The part of the grate that the pot sits on is directly over the fire and all absorbed taste etc. gets burnt up. Therefore according to numerous poskim it is fine. If is there is residue there it should be wiped off before putting the pot on it. There are opinions though that it is preferred that one use different fires for milk and meat.
Rema O:CH 151-4, M:B ibid 34, Igros Moshe Y:D 1-59, Ksav Sofer Y:D 54, Kovetz M’bais Levi 1 pg. 29.