Mackenzie Shirilla Cashed In On Sugar Daddy Sites In Jail, Ex-Inmate Claims

Mackenzie Shirilla apparently kept her hustle going behind bars ... at least according to a former inmate who says she found creative ways to make money while locked up.

Kat Crowder, who says she spent six months in prison with Shirilla, tells TMZ Mackenzie got crafty with an arts kit -- making jewelry, including nose rings, bracelets, and custom shoes ... claiming Mackenzie told people if they wanted something, they could pay up via Cash App.

Catch the full clip ... 'cause Kat refers to the platforms Mackenzie was active on as "sugar daddy" websites -- though she says that label was more jail slang than literal.

Kat says she doesn’t think Mackenzie’s still using those sites now that more people have found out ... but adds she wouldn’t be shocked if she got plenty of attention through them.