Foley, who played 20 times for United and scored three goals in the late 60s, says that racial abuse was common on football pitches throughout the country.
Ron Atkinson, who has had to resign from his job as an ITV football pundit after using a racist term to describe Chelsea captain Marcel Desailly, was one of many players to target him.
Foley played against Atkinson three times, who was a player with Oxford United.
He told the News & Star, newspaper: "He called me a black this-and-that, along with every other player I played against.
"Ron would call me names like every other player, but I didn't find him racist.
"Ron doesn't think before he speaks, we all say silly things."
Foley also claims he was kept out of the Scunthorpe first team because of the colour of his skin.
The Glasgow-born player moved to the Old Showground from Workington in 1967, moving to Chesterfield two years later.