Originally Posted by TangoTango
MEK is otherwise known as Methyl Ethyl Ketone. Acetone is a similar molecule, basically it is one carbon atom shorter. However, just because it is nearly the same does not mean it will have similar properties.
Actually, in this case, as is the usual case with organic molecule families they will indeed have "similar properties". Both Acetone (aka propanone) and MEK (aka butanone) are both ketones; Acetone is the simplest ketone and, as noted above, MEK is the next ketone up from acetone. Without looking up the properties, its a pretty safe bet that acetone has a lower density, a lower viscosity and a lower evaporation point than MEK but will act similarly as solvents. MEK may be the recommended solvent for this particular application as it will not evaporate quite so rapidly.
In other words - you should be fine with acetone if MEK was recommended. Just test an inconspicuous area first with a small amount on a cloth and make sure it's not too aggressive.
But, as noted, it can be very different for inorganic compounds that have apparently similar formulae.