Weird question about hardness

The folks I know who are in the trade have a special set of small files and by using those files on any kind of metal they can give you an exact hardness rating. I suspect it it is low?

 

Most all metals are not used in the pure state. They are alloyed with other metals. The hardness of metals will depend on the allow and the temper. 7075 aluminum, for example, is harder that 6061 and much harder than 3003.

The same issue varies with plastics. PEEK is much harder than nylon 6-6 which in much harder than HDPE.

 

For the EGR cooler only: powdered Oxy-Clean dissolved in hot tap water, as concentrated as you can make it. Soak for about an hour, rinse and repeat. If extremely clogged, use thin copper wire as needed to open up passages, allow the solution to penetrate.

Others have used oven cleaner, and/or pressure washer.

For most everything else but the MAF: brake cleaner.

For MAF, a specific MAF sensor cleaner, CRC makes one.

No, should be fine. I use old tooth brushes, bottle brushes.