Assuming you mean, are the words "clean those brass" adjectives, the answer is no, maybe, and yes
Clean is a verb.
Those is a demonstrative pronoun. (Some people might call this a form of adjective, as it is a modifier.)
Brass is an adjective: a brass Trumpet, a brass bookend. Note that brass is also a noun in some uses: the brass on that uniform is shiny, the brass in this orchestra is very good
The adjectives are clean
clean
There are no nouns for adjectives bro. There's not going to be a noun for blue so there's not going to be one for those.
You can clean a brass telescope. Over a duration of time, brass starts to oxidize. To remove this, can use vinegar and salt. You can also use a concoction of chemicals that is premade, usually by a company that specializes in brass.
http://home.howstuffworks.com/how-to-clean-furnishings3.htm
This That These Those are some demonstrative adjectives
There is an effective way to clean brass door knobs. The first thing they need is to determine if the knob is brass plated or solid. If it is plated, use caution in the cleaner that they use.
Hopefully, these adjectives: clean, pleasant, popular, inexpensive, accessible, roomy, efficient.
Brass will oxidize and turn greenish. Moen and Delta have PVD brass finishes which are more resistant to corrosion.
To clean your brass plate, you get some brass or silver polish and start cleaning. If it is something you just look at, you can put varnish over it after you make it nice and shiny. Ketchup. Best brass or silver cleaner on the market. paint it on with a small brush and allow to sit about 10 minutes and wash it off with clear clean warm water
There are many different natural products you use in your home that will clean brass really well. These include ketchup, soap, vinegar, water, and lemon juice.
That, This, These, Those