[jQuery] trying to do Math.min on 3 tds by excluding if one = 0

Hi,

I'm trying to do Math.min on 3 tds by excluding the ones = 0

<td class="m0" width="145" style="text-align: center;" price="0">7.5</
td>
<td class="m1" width="145" style="text-align: center;"
price="7.25">7.25</td>
<td class="m2" width="145" style="text-align: center;" price="0">0</
td>

i want to exclude the one = 0

i'm using this actually

$("tr." + i).each(function () {
var ithis = $("tr." + i + " td:lt(3)").min();

$("tr." + i + " td.r1").empty().append(roundVal(ithis));
});

thanks for help