a bird can't tell the differnece between a perch and a toy. they just chew. don't let this bother you. next time get a harder perch. some wood is so hard budgies can't chew them. or try a rope perch, but be careful, when those get frayed the bird's nails can get stuck in them, so you gotta trim any frayed ends of the rope perch. a change of perches once in a while is good for 'em anyway.
i don't think parrots need grit, in fact, it can kill them. for a long time ppl thought parrots needed grit, but now ppl know better, but pet stores still sell it. here is my source about the infor for the grit -- please read it
http://www.the-oasis.org/articles/grit.php
other kinds of birds, the kinds with streight beaks like sparrows or for pet birds, i guess doves and cararies, need grit, but not hook-bills like parrots.
anyway, we had to hammer bird-safe wood onto the painted and treated window-sills in my dad's african grey's room to keep our afriacan grey from chewing on poison wood when he sits next to the window. this way he can chew the planks of wood he sits on without poisoning himself. they are gonna chew. the only thing you can do is make sure they can't get to what you don't want them to chew, and a perch in a cage isn't one of those things you can (or should) stop them from chewing.