No "No Vote" Option

One thing has always deeply troubled me about Washington's mail-in ballots, and this year, I find it more disturbing than at any point in the past. I have selected two non-partisan offices on the current ballot to illustrate my point. I fancy myself an informed voter. I read all the text in the voter's pamphlet, not just the candidates' statements and arguments, but also the full text of any initiative or referendum which happens to appear. I study carefully who endorses candidates and issues, and based on what I have read, I decide how to cast my vote, yea or nay. In the case of these two positions, I know absolutely nothing about the candidates. I do not want to idly fill in a box, not knowing where they might stand. Do you see the problem yet? There is no "no vote" option! If I do not want to vote for either candidate, there is no way to indicate that I am withholding my vote. Despite what I know from having worked at the polls years ago, and from what friends who work at the polls currently have told me, I see potential for abuse here. They claim that because there is always more than one person involved at every stage in handling of ballots that the chance of someone changing a ballot is very slim...but it exists, moreso if no candidate has been selected. Let me say, "No, I don't want to vote for either of these people." Don't make me just flip a coin.