You can gain enough traction on ice to move 5 feet in 6 seconds (tested on many of ice hockey rinks and frozen ponds/creeks...even when the ice is melting and its especially slippery) its actually pretty easy. With grease it would depend on what it's covering. If the substance underneath is jagged or rough it should be easy enough to find footing/traction. If for some reason your on a glass floor with grease on it, it could be more difficult.
I suggest someone test this and post results.