Leftover clonazepam in the system is not the problem, it's the damage to teh GABA receptors. I came off benzos nearly three years ago and I had a horrific withdrawal. To this day, I still cannot drink alcohol and have it effect me like a normal person.
I spent years on benzo withdrawal "support" forums, although if anyone knows what went down on those forums in the past years, they will understand why support is in quotations. Anyway, the majority of people who came off benzos reported that drinking alcohol threw them back into benzo withdrawals, sometimes for months or years after one night of drinking. The terrifying thing is that some people claimed they were completely healed from benzos, drank a pint of beer and were thrwon backl into benzo withdrawal for the next few years. Nothing like that happened to me thankfullly. All that happened to me when i tried drinking was that, it was no longer fun or enjoyable like it used to be before benzo wd, i didnt get any euphoria from it nor did i even get relief from my benzo wd symptosm. it was like the benzo wd over powered the alcohol. Then the next day, i woke up with a hangover (even though i only drank 4.5 beers) and some inner vibrations (which was a benzo symptom) that may have been brought back by the alcohol. Luckily I was fine by the next day, so I had no reall problems with alcohol, i just didn't enjoy it and I havent really seen it worth risking drinking again. I did have a little whiskey recently and some wine on another occasion, but again, both times i did not enjoy the effects.
So wherther you want to take the risk is up to you, but personally i dont see it as being worth the risk. If you want to get buzzed, use a non GABAergic drug. For example, I became a heroin addict.