Thank you both for your replies.
I'm not sure I understand. One of you went to some trouble posting a screencap of the View menu for me, as though I simply could not find where the Clean Up command was.
That was not my question.
Let me clarify. I want to Clean Up Selection—this is a standard variation of the Clean Up command in Finder going back over twenty years. I do not want to clean up or sort my entire desktop... I want to clean up a selection of icons, and leave the rest of them where they lay.
I know where the Clean Up menu item is. If the Clean Up menu item did what I wanted, I would not be here asking the question. The Clean Up command wants to organize my entire desktop. I'm not interested in this. I just want to straighten out a subset of icons.
Surely I cannot be the only Mac user here who remembers this command or has need for it today in Yosemite.
I have tried to hold down command, option, shift, control, and combinations of these to make the Clean Up Selection command appear, but nothing I've tried so far seems to do it. In the past, this is how the MacOS would allow for obscure (?) yet still useful functionality to be accessible. (I fail to see what is obscure about this command, though. It has been a mainstay of the Finder since I can remember.)
Am I to assume that Apple has removed this functionality? Once again disposing of something useful in MacOS because there is no corresponding command in iOS?