The tarnish can be easily REMOVED with polish. What part of speech does the word in capital letters play this sentence?

The word "REMOVED" in the sentence is the past participle of the verb "remove".

Here's why:

* Past participles are often used to form the passive voice, which is what's happening in this sentence. The tarnish is being acted upon (removed) by the polish.

* Past participles can also act as adjectives, but in this case, "removed" is functioning as part of the verb phrase "can be easily REMOVED".