Combining vars not working...mc.mask

can anyone help me figure out why the following doesnt work:


for (var i = 1; i < 6; i++) {
   var mc = "mc"+i;
   var mask = "mask"+i;
   mc.mask._xscale = 50;
 }

BUT, if i change the line mc.mask._xscale to mc1.mask1._xscale, it will work.

i also put a trace(mc) and trace(mask) and it spits out mc1, mc2…mc5 and mask1 to mask5.

wat am i doing wrong?
thanks.