Caleb said:
Is there a way to open up two runescape browsers at once?
If you want to trade between accounts, sadly no. You either use two computers, or get a very trustworthy friend to hold the items whilst you log on to your other account.
If I were you I would ask someone from TBT. That way, they can hardly log out and never see you again; you wil still be able to contact them on TBT, so they would probably not steal your items. I'm always up for helping with that sort of thing, and you can trust me