Excel: =TRIM(CLEAN(SUBSTITUTE(A1,CHAR(160)," ")))

Quite often the issue is a non-breaking space - CHAR(160) - especially from Web text sources -that CLEAN can't remove, so I would go a step further than this and try a formula like this which replaces any non-breaking spaces with a standard one
=TRIM(CLEAN(SUBSTITUTE(A1,CHAR(160)," ")))
Ron de Bruin has an excellent post on tips for cleaning data here
You can also remove the CHAR(160) directly without a workaround formula by

• Edit .... Replace your selected data,
• in Find What hold ALT and type 0160 using the numeric keypad
• Leave Replace With as blank and select Replace All