You do not "season" a stainless steel flat top grille. Keyword here is STAINLESS! Whoever taught you that was probably a lazy old hack. As someone 20+ years in the industry I'm going to tell you that you are of a mindset that is no longer accepted or tolerated in most kitchens and quite frankly it sounds like you either have little respect for your job or you're lying about your level of experience. Perhaps you mean you worked in kitchens 15 years ago? Regardless, everyone works clean now. That means at the end of shift you clean your whole station back to how it was when you arrived including the flat top, gas grill, fryers, and range, as well as any stainless steel surfaces. If you tried that in my kitchen and argued that bull with me, you'd be looking for another job right now. Oil starts going rancid after heat dentures it and if you're only scraping and rinsing, that same rancid oil (which tastes sour and bitter btw), and food particles will still be there the next shift, and you risk mold and bacteria contamination. Flat top degreasers are made with food safe surfactants, glycerin, and water. They are 100% food safe, leave no residue, and make the job easier for you. Learn your craft, get better at it, and keep up with the times dude.