Sorry Elle...

...I know that sucks!!
I have tried everything over the years to make these work for folks...
I have slathered them with wax, 10 coats of lime wash, (even cement wash which I just despise using), box them in with wood, and many other esoteric "maybe this will work" kind'a things...
NO GO...As Dale suggested...never by food or garden, and I now won't even try to use them for anything as cutting them is hideous...
Sorry again for being a bummer...