I use a Tupperware sandwich keeper - five or so wipes fit in there nicely, folded in quarters. It becomes part of our getting ready to leave routine - nappies, tote bag, wipes. Pre-wet and folded, into the container.

Likewise when we get home - tote bag out, empty nappies into bucket, empty unused wipes into bucket, leave container to air dry. No mould, no dramas. Too easy.

ETA - just in case it wasn't clear - I only wet them with water. I have some Itty Bitty and some Motherease (maybe) cloth wipes.