As stated before, this nubby, rubberish feeling has occurred on other cars, at different times and in different ares; whereas the unaffected areas are smooth. Although claying would probably remove whatever is causing the problem, I will first try ZAIO in the affected areas. If this doesn't work (almost quite sure it will), I'll then try some compound. After removal, will do Z2 in the areas...making sure that applicator is clean and things have adequate time to dry.
I'm a little confused. Claying is the least aggressive option in this case. Certainly a lot less aggressive compared to a compound. The worst case scenario when using the clay bar is if you have really soft black paint and it produces marring. In that case, a finishing polish would be all that you would need to remove the marring and produce a brilliant finish.
Although claying would probably remove whatever is causing the problem
If that is the case, then why don't you try it first. A polish, such as Zaino AIO, would not remove the contaminants as effectively as a clay bar. Also, if Zaino AIO is a chemical cleanser and not an abrasive polish, then it may not remove the embedded contaminants (I have no experience with Zaino products, that's why I can't comment on the makeup of the product).
If you don't have a clay bar, they are available over-the-counter from any automotive or big-box superstore (Wal-Mart, Target, etc.). I would pick one up - you never know when it may come in handy. As you've said, this has happened before, in different areas, on different cars. Most would agree that unless your car is coated (which yours is not if you have Zaino products on it), then you should be claying at least once a year.
If you wanted to stay within one brand, I'm sure Zaino sells clay, but truth be told, they're pretty much the exact same - the only difference is the aggressiveness, or "grade". The OTC clay is mild, however you can probably get aggressive clay if you needed it. The only downside to aggressive clay is a polishing step is most likely needed due to clay-induced marring. If you need something milder, Sonus and Pinnacle have the two gentlest clays available. I have experience with Sonus clay (when Meguiar's OTC clay marred, the Sonus did not!)
Remember, you don't want to polish or compound if you don't need to - the clear coat on your car is finite, and you'll want as much as possible there so you can polish away scratches for years to come. In my opinion, this is
not a case where you would want to break out the compound. Check out the threads on claying and the educational material on above-surface embedded contaminants. There is great information to be learned!
Happy detailing!