Pia's pet sure tears up delicate stuff (6,5)
I believe the answer is:
tissue paper
'up delicate stuff' is the definition.
'tissue paper' can be an answer for 'stuff' (tissue paper is a kind of stuff). I am unsure of the 'up delicate' bit.
'pia's pet sure tears' is the wordplay.
'tears' indicates anagramming the letters.
'pias'+'pet'+'sure'='piaspetsure'
'piaspetsure' with letters rearranged gives 'TISSUE-PAPER'.
Can you help me to learn more?
(Other definitions for tissue paper that I've seen before include "Kleenex" , "There may be a valuable article in it!" , "Wrapping for delicate objects" , "delicate sheets" .)