Polish workers on increase (7)
I believe the answer is:
beeswax
'polish' is the definition.
(I've seen this before)
'workers on increase' is the wordplay.
'workers' becomes 'bees'.
'on' says to put letters next to each other.
'increase' becomes 'wax' (waxing is a kind of increasing).
'bees'+'wax'='BEESWAX'
(Other definitions for beeswax that I've seen before include "Hive-made polish" , "Honeycomb material" , "Furniture polish" , "Material in honeycombs" , "Animal product for polish and candles" .)