I tried cutting a copper wire once to get some of the sea into a glass, but somehow it always stopped before I could get anything.(/sarc)
Going from memory, you need to be travelling at something like 0.01c to measure the fraction of 1mm contraction due to ETR/Lorentz. So you would need to be travelling at 10 billion km/hour to shrink by 1mm ... assuming you were travelling head first.
Still fast, but 100 times slower than the speed of light. Like walking on the autobahn.
