[RileyD]

I have an old Dynaco ST-400 Amp that needs some TLC.  It functions perfectly, and the faceplate is very clean.  But the steel chassis is showing some corrosion and smudging.
What is the easiest and best way to clean the old chassis?
Thanks

[dB Cooper]

I would reach out via PM or email or phone to Frank van Alstine, who built his equipment in old Dyna chassis (including the ST-400) for years. He knows these boxes better than anyone.