Here is the legend, there were parts of a lawn chair placed into the run, and beer cans and silver coins, just about any metal which would melt with temperature. "LAWNCHAIR" became the name the JABO Metallics became known for from images which circulated on the marble boards showing a cut up aluminum and fiberglass lawn chair, near the furnace. I wasn't there and only a handful of folks were. Burt Wilkins, you care to elaborate?

As to who added the Lawn Chair-
Here is a post from 2016, Ron Shepherd writing as wvron on the All About Marbles board:

"It was myself and Dave McCullogh. I held the lawnchair while Dave used a hacksaw to cut the hallow legs into about 1/8 thickness. Then they went into the tank near the front or orfice exit. I had been experiment with adding different types and temperature welding and brazing rods to the stream of hot glass going to the shear. So Dave said lets put some aluminum in the tank. Dave did the experiment at least three or four different times. The marbles were both 5/8 and 3/4 size. Most were dark colored but some of the 3/4 are green red and yellow along with the silver aluminum. The aluminum is on the surface but also inside the marble. If it does not burn up at 1700-2500 degrees or all go inside ? You might find it in or on a marble. Some could be one of a kind or some could be one of six or a dozen. Or like the Lawnchair marbles a few thousand."