No radio or heat/air in the car now. I had speaker grills in front to cover up the corner but served no functional purpose so they are coming out for a cleaner look.

I have to cap off the heater tubes.

Spray can tops?

What's the best use of this area? How did non-radio cars look? Are the tubes exposed? Carpeting over or behind?

Thinking it may be a good spot for an extinguisher?

I believe they still had the grills, just with no speakers behind them.

Gary,
Powder coating places have caps to cover holes. I think Eastwood even sells a variety of them. Check that out...

I was thinking finding metals caps that I can graft a fire extinguisher bracket to..