My Taiwanese boss treats me like a cog, disposing of me when they run out(??). Nowadays I work in a global company where my boss treats me like a treasure. He does his best to keep me working with him. Your first sentence does not make sense to me. To what does "they" refer? Is the Taiwanese boss a former boss? If so, use past tense: "treated me", "disposed of me". I also don't understand "run out". Perhaps "grind down" or "burn out" are metaphors you might use. I prefer "to keep me as an employee", but it is fine as you wrote it.