Superheating steel or gold bars gets smithing exp as well. It's smart to do this if you need to get your smithing up for quests or just want to have high smithing. I personally will probably superheat a combination of gold and steel bars to get at least level 70 smithing, maybe even higher. Currently superheated gold and steel bars to level 43-65 smithing.
Gold bar superheating is 94-98k SMITHING exp per hour AND 90k MAGIC exp per hour (but sufficient losses, I make my own nature runes so it's not really that much of a loss for me, but its more if you don't)
Superheating steel bar's 20k SMITHING exp per hour, 87k MAGIC exp per hour and makes like 200k per hour
Good luck buddy.
Also if you have 4M to spend on magic how about paying me back the 3M you've owed me the past month and a half ^_^