After waxing and baking my Inov8 Roclite 296s to try and restore their waterproofing, I went with some friends from school to the north west of Scotland (write up to follow), where the waterproofing was very much put through its paces.
Unfortunately, my experiment did not re-proof my boots – I had damp feet for pretty much the whole week – but it did provide a rather unexpected benefit: the increased hydrophobicity of the outer mesh meant that mud and dirt had a hard time sticking to the boots, and so I ended the days with mostly clean, albeit damp boots.
So in summary:
Greenland wax won’t re-waterproof lightweight mesh boots, but will hugely reduce dirt sticking to the boots.
Using the wax at the start of a boot’s lifetime may help maintain the boot’s waterproofing by preventing dirt from penetrating the outer fabric and abrading the inner membrane.
Leather boots would probably be fully re-proofed…
Hope this helps :).