Eliminating zero values from matrices

I have the following example matrix:

1     2     3

0     0     0

0     0     0

4     5     6

7     8     9    

0     0     0

1     1     1

I'm trying to write a function that processes this matrix to eliminate Zero values, such that result is:\

1     2     3

4     5     6

7     8     9

1     1     1

Any help/suggestions would be appreciated.

Thanks,

Matt