5e OGL - Creating New Skills

So, a quick question I would like to ask. I'm trying to run a campaing with a new skill in it, Crafting. I was trying to use the Tool Proficiency box for that, but I just realized that you cannot set a skills as unproficient in that box! You could add a negative modifier to the skill equal to the character profiency...But that sounds so diselegant... Is there a solution for adding a new skill that does not involve getting a pro subscription (I would love to get one, but money is really tight right now). 

I don't use the sheet in question so cant comment on the specific problem. But speaking more generally, if you're planning on using the 5e OGL by Roll20 sheet, getting a Pro subscription wont help much either. The By Roll20 sheets are becoming incompatible with the Custom Sheet feature, because they have access to backend features that the community doesnt have. I know the 5e sheet has some appearance tweaks that cant be reproduced with custom sheets, and I expect there'll be bigger differences over time.

The legacy sheet can probably still be tweaked? But yeah, inelegant as it is, you've probably hit on the best method, André.