Are, in certain ways, general goods (5)
I believe the answer is:
wares
'ways general goods' is the definition.
'wares' can be an answer for 'goods' (wares is a kind of goods). I am not sure about the 'ways general' bit.
'are in certain' is the wordplay.
'in' indicates putting letters inside.
'certain' becomes 'ws' (I can't explain this - if you can you should give a lot more credence to this answer).
'are' put into 'ws' is 'WARES'.
Can you help me to learn more?
(Other definitions for wares that I've seen before include "Merchandise" , "Stock and products - swear it" , "Goods for sale - swear it" .)