i would stick to plastic scraper. Metal ones removes base material which you dont want to do.
Go to swix.com they have alot of GOOD videos that shows you to sharpen and wax PROPERLY.
Most of the videos on youtube is completely crap. Stick to how swix does it. They have different levels of waxing from recreational to racers. You can use good rub ons/ spray ons on your base(extruded). There isnt a huge difference between rub ons and hot waxing on EXTRUDED bases. On sintered bases there is a huge difference but i am pretty sure you have extruded bases. And get waxing iron. DO NOT USE CLOTHING IRON!!!! it is very easy to burn your bases as well as loosening up resins that are used to hold different layers of snowboard and inserts. And make sure you remove bindings everytime you wax.