Now for me to make the second non-noobish post in this whole topic. While I personally am against the idea, as it definantly would not go with the general RS theme, but the concept could be modified into some type of thrown weapon, though different from modern grenades. Like smithing the shell from iron and using herblore to make an explosive potion (much like those in Castle Wars), and using it with the shell to make an explosive which you can weild like a normal thrown weapon (though you couldn't get it back after you used it), but would deal heavy damage to multiple targets. Your idea doesn't fit with RS theme, but if modified, it could work.