Used to could.

source: 
LAGS
Entry: 
663
Example: 
Used to could.
Modal 1: 
used to
Modal 2: 
could
Gender: 
Female
Race/Ethnicity: 
White
Age: 
70
Level of Education: 
College (Graduate, B.S. degree)
Home Community, Town, or State: 
AL (Stockton)
Location Collected: 
AL (Stockton)
Year: 
1977
Relation to Addressee: 
subject to fieldworker
Medium: 
Spoken
Sentence Structure: 
unknown
Status: 
Naturalistic