How about a combination of the two? A telescopic arm positions its payload over the given cleaning target, and releases a small cleaning robot tethered on a str

How about a combination of the two? A telescopic arm positions its payload over the given cleaning target, and releases a small cleaning robot tethered on a string. The "spider" has the tech to minutely go over the surface of the target and clean it, while the arm has only the "macro" capabilities.