Odd minty smell on wet nappies

[AngelDog]

I did a nappy wash last night and didn't get chance to hang it out so it's still wet 24 hours later. The muslins I use as nappies and the flannel wet wipes smell really odd - a kind of minty type smell, not entirely pleasant.

I've had this before on food bibs which are plastic backed and fleece-fronted - they got black mould type spots on them eventually.

Any idea what it could be and how to deal with it?

I do a reasonably regular maintenance wash, the machine is in good condition. I normally use soapnuts, though this latest wash was done with bio coloured washing powder and soda crystals.

I would think it is just that they have been wet. I would rewash and see if it is still there.