This spring I had cuttings in six plastic boxes with clear lids (think Chinese take out). The lids seal quite well in these. Each box had anywhere from 2 to six cuttings. I had two boxes of cuttings out of six that developed some off odors and mold.  Most of the cuttings in those boxes did not root but some did. I gently washed the moldy ones and then put the cleaned cuttings into different boxes that had sucessfully rooted cuttings. I retained the previously used mix from the new box and did not add any water. The moldy medium I tossed and then ran the empty boxes through the dishwasher to sterilize them for use next time. Hopefully next month I'll have some more rooted cuttings to pot up.

Another forum member recommended physan 20 as a good mold killer.  I've had good results with not losing cuttings that were moldy and rooted ones that were exposed to mold.  So far the moldy ones look healthy but no roots yet.