Squeeze it, before applying Clearasil, perhaps (4)
I believe the answer is:
tube
'clearasil perhaps' is the definition.
I can't tell whether this definition defines the answer.
'squeeze it before' is the wordplay.
'squeeze' becomes 'ube' (I can't justify this - if you can you should give a lot more credence to this answer).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'before' means one lot of letters go next to another.
'ube' put after 't' is 'TUBE'.
'applying' is the link.
Can you help me to learn more?
(Other definitions for tube that I've seen before include "train network" , "Hollow cylindrical object" , "Hollow body for the underground" , "Transport system" , "London Underground or long cylinder" .)