Soak through (8)
(Other definitions for saturate that I've seen before include "steep" , "Drench thoroughly, soak" , "Infuse or fill completely" , "Oversupply" , "Soak completely" .)
'soak through' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for permeate that I've seen before include "Percolate" , "Flow or spread into every part of" , "Infiltrate" , "Imbue, spread through" , "Seep through" .)