Scott Dorsey wrote:
Chuck Harris wrote:
One thing, from the ingredient list I posted earlier is Formula 409
contains Butyl Cellosolve. This is terrible stuff on plastics. It is
what turns clear plastic molded meter windows foggy. I would not use
Formula 409, or any other cleaner that contains Butyl Cellosolve on
plastics of any sort. The stuff soaks into the plastic and makes it
sticky and soft... sort of a plasticizer.

It's fine on most plastics. It's a disaster on others, most notably
phenolics. It will etch the hell out of bakelite and leave you an ugly
dull surface. Test before using.
--scott

Ford cars all come with warnings not to use cleaners containing
butyl cellosolve on, or around the instrument panel. They tell of the
damage they will cause to the speedometer window... And I have ignored the
warning with 409, and other glass cleaners, and fogged the dash windows.

I used to use 409 as a general cleaning agent on surplus test equipment,
until I started to notice that I was ending up with power cords that
became sticky, plastic tote handles that became sticky, and wrinkle paint
that became softened and sticky. All anecdotal evidence, I know, but
much of this equipment survived 20 years before my cleaning them with
409 without these failures occurring.

Butyl cellosolve is used because it is an incredible penetrating agent.
It burrows deeply into grease and grime, and softens it so that normal
detergents can wash it away. It also does this to many plastics and
rubbers. I believe that clear plastics that are polystyrene based are
particularly affected by 409.

If you do use 409, always rinse it away with water, never just spray
and wipe, as the manufacturer recommends.

Isopropyl alcohol is a great solvent for cleaning, but it too can cause
problems with some plastics. Never leave acrylics soaking in isopropyl,
as it will cause them to form deep cracks without ever softening the
plastic.

-Chuck