Lie-ins for cleaners? (5)

I believe the answer is:
baths
This could be a double definition.
'lie-ins' is the first definition.
The answer and definition can be both acts as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'cleaners?' is the second definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'for' acts as a link.
Can you help me to learn more?
(Other definitions for baths that I've seen before include "Large tubs" , "Public swimming pool - ablutions" , "an answer to all clues, initially" , "recreation centre" , "water-containers" .)