Difference between - 'Clean out', 'Clean off', 'Clean up' & 'Clean away'...

source: Learn English with Let's Talk       2013年7月23日
Spaces and messes
When you talk about cleaning, you're talking about two different things:

the space that you're cleaning
the mess that's in that space

You can use each form of "clean" to talk about either cleaning the space:
eg. We need to clean up the living room.
ORcleaning the mess that's there:
eg. We need to clean up those dirty dishes.

The different forms of 'clean'
You "clean out" the inside of a space that has a large mess in it:

clean out the refridgerator
clean out your car
clean out your desk
You "clean off" a flat surface:

clean off the counter
clean off the whiteboard
clean off your windshield
You "clean up" a room or a larger area:

clean up your bedroom
clean up the city
clean up after the concert
clean up your hard drive
"Clean away" is different from the others because you only use it to talk about the messy things that you're cleaning, not the space that those things are in:

clean away the dishes
clean away the mud
clean away the broken branches
'Clean' by itself
What about just using the word "clean" by itself?

It usually means to clean the most obvious part of something. For example:

clean the toilet
This means to clean the inside of the toilet bowl.

clean the floor
This means to clean the surface of the floor.

If using the word "clean" by itself would lead to any confusion, use one of the other phrases instead. For example, instead of saying "clean the cabinets", say:

Can you clean out the cabinets?
Can you clean off the cabinets?