Hi Joshua,
Welcome to the VWBB!
Those traingular pieces ae called "Flavorizer Bars". If they are in good condition but just crusty, you can heat them up and brush them with a wire brush. (Don't burn yourself)
Or you can try some Easy Off oven cleaner. Lay them out on some old newspaper. Follow the directions and beware of the fumes.
If they are shot, replacements are available online or in most decent hardware stores. ACE hdware is Weber delaer. Some are porcelain coated, others are stainless steel. The latter being the more desirable. Do you have the owners manual? If not you can find it at Weber.com. If you are handy enough, the serial number should be located on or under the plate that has the control knobs on them. The serial number enables you to find parts and manuals veery easy. Also, if youa re cleaning it and it hasn't been used in a while, beware of spiders. They like to hide inside the burner tubes. So much that Weber has installed small plastic vents on the burner tubes to try and keep them out. Read the manual on how to clean them. Beware that they are plastic and break easily. They're cheap enough, but you probably need to order them,so be advised that Weber charges a flat rate price for shipping. Ocasionally they will have a promotion for free shipping, just keep an eye out on this site, someome will post it.
One last thing, when you get it going, be sure to post some pics of that grill in action!
Good Luck and Happy Queing!