They're used by those that dry up - there's a lot in train (8)
I believe the answer is:
teacloth
'they're used by those that dry up' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'a lot in train' is the wordplay.
'in' indicates putting letters inside.
'train' becomes 'teach' (I've seen this before).
'lot' placed within 'teach' is 'TEACLOTH'.
'there's' acts as a link.
Can you help me to learn more?
(Other definitions for teacloth that I've seen before include "Kitchen towel" , "Drying-up towel" , "Washing up dryer" , "Washing-up drier" , "It's used for drying up" .)