Is there any way for a high-level toon to "powerlevel" low level toons?

[Hardcore Scape]

Any boosting has to be done open world from my testing. Even if you leave the group while in the dungeon everyone in the dungeon gets split XP. I've been boosting my friend open world and I've gotten him 150-200k xp/hour from lvl 45 to 55. He uses oils and dynamite to tag since he's a rogue while I round everything up with demo shout. After he tags I AOE with mages and warlock.

If you want to be able to help kill the mobs on your 60s the mob has to be not a skull for them and at least green for you (48+ at lvl 60) else all you can do is tank with non hitting abilities and heal outside group