Rename is an option for Contract. If set to
True, dummy indices in Eps are renamed, using
$MU[i].
LC[\[Mu], \[Nu], \[Rho], \[Sigma]] LC[\[Alpha], \[Nu], \[Rho], \[Sigma]]
Contract[%, EpsContract -> False, Rename -> True]\bar{\epsilon }^{\alpha \nu \rho \sigma } \bar{\epsilon }^{\mu \nu \rho \sigma }
\bar{\epsilon }^{\alpha \nu \rho \sigma } \bar{\epsilon }^{\mu \nu \rho \sigma }