My iron plate needs cleaning any suggestions to get it smooth????

If you put down some wax paper then spread some salt on it and turn iron on and iron over it until the plate it clean and give it a wipe.

https://www.thespruce.com/how-to-clean-an-iron-2146972

Baking soda or barkeepers friend.

Rub warm iron with bar of soap then iron on old scrap of cloth

will try Thank you any more suggestions??????????????

Barkeepers Friend is a very mild abrasive cleaning and polishing compound found at the grocery store next to the other cleansers of its type, like Comet. More to the question: you said that the salt and waxed paper worked before but not this time. if you are needing to do this on a repetitive basis, may I ask what you are using the iron for, since ironing laundry does not cause any damage to the sole plate. This would be most helpful in perhaps preventing it from happening again. As for smooth, you are dealing with an electroplated stainless steel surface. If its scratched there's nothing to be done other than smoothing it down so the scratch does not damage clothing. If its a buildup, i definitely need to know what it is before I talk about removal. If you wish to continue this, contact me at: mhdubow@yahoo.com

On a cool iron dampen a cloth and dip it in baking soda and rub your iron plate until the yuk is gone. Barkeepers friend can be bought in most stores . It is located with things like Comet. Barkeepers Friend will not scratch surfaces like other cleaners but is a lot more expensive than baking soda.

Buy a new iron !!

I used the instructions in the link, the baking soda /water paste worked great! https://www.realsimple.com/home-organizing/cleaning/laundry/clean-iron