I think it would be far more productive to raise your forging/crafting skill levels. If you are below level 50 I would suggest just using iron to upgrade broadswords and cheap bracelets. If you are above level 50 I would suggest using orange grass to upgrade broadswords and cheap bracelets. Orange grass can sometimes be bought at the clinic after you have shipped it for about 180G per piece and a stack of nine will generally get you at least one increase in skill level up into the 70-90 range. If you want to restore RP I would suggest using Toast which is an oven recipe using Bread which uses Flour, and will restore 800 RP. It may be more effective to use only iron, as it will take less RP to do so but I have found that upgrades seem to give more experience when the upgrade material and the item being upgraded are more of a higher grade.