Question: In my open-space office our 5-man team, "A" sits next to 8-man team "B". About 3 weeks ago, a colleague from HR came and asked team "B" to mind their behaviour because they were rather loud and tended to swear quite a bit.

In order to accommodate quickly, they decided that for each curse one has to throw some change into a jar. Their method proved effective, as they control each other strictly.

About a week later, they suggested that our team join their "jar fund" and everyone except me agreed to do so. It is not a matter of the insignificant fine amount, but rather that I do not wish to be monitored in such a manner, despite the fact that I hardly ever swear (definitely the least of them all). I explained why I wouldn't take part and deemed this issue settled.

However, one team "B" member keeps nagging me about paying the fine for my grand total of 2 curses (something silly like "damn," no less) basically every day and completely ignores the fact that I'm not taking part. I clearly let him know multiple times that he's being annoying but he doesn't seem to care. At this point, I've definitely ran out of patience and will probably get very unpleasant very soon.

Generally, I would not hold back but I don't want to perform a full-fledged rant at work.

I could notify his superior, but I would rather deal with it personally. To make it clear: I no longer care about having a good relationship with that person, but I don't want to be "that guy" who reports others for generally insignificant reasons.

What is the best way to handle this situation?

**Update:**

So it turns out that the problem fixed itself as the nagging coworker received a notice due to multiple complaints from the client regarding his lack of commitment and work ethic and was allowed to leave immediately.

Answer: 
Put a jar on your desk labeled "Nag Jar 25 cents" and insist that he drop in a quarter every time he mentions the swear jar.
My suggestion (which has worked for me in analogous situations):

1. "I am allergic to collective coercion." [the first nag of each week]
2. "It's still a no, I am afraid." [after that, for a few times]
3. "It's still a no." [for the rest of the day]
4. "No." [for the rest of the week]

Always said in even and unperturbed voice, no matter how often it is repeated.

Don't even try to convince them to stop nagging. That's the key.