Matrix - Replace zero by blank

I have some large Matrix visuals with also many Zero's (0) in there. To improve readability I would like to replace the Zero by Blank or something else e.g. "-". Google gives many tips on how to replace blanks by zero, but not on replacing zero by blank.

Good to know: These zero can occure in two ways; 1) the value is acutal zero, or 2) it is a blank which appears zero in the matrix. In the matrix visual both should be replaced from zero to blank or something like "-"