From the wonderful RedGuides Wiki

This command is added by MacroQuest

Syntax Key
Notation Description
Text without brackets or braces Required items
<Text inside angle brackets> Placeholder for which you must supply a value
[Text inside square brackets] Optional items
Vertical bar (|) Separator for mutually exclusive items; choose one
{Text | inside | braces} Set of required items; choose one
Ellipsis () Items that can be repeated
Syntax /cleanup
Description Closes all open windows. Common abbreviation: /clean




"/clean" is actually performing escapes, so if you don't have windows set to "escape to close" those windows won't get closed with a /clean [1]

See also