Your life will be happier and more complete if you don't ask that question.

Okey lets start with the standard disclaimer when it comes to ancient coinage. The study of ancient coinage is a bit of a messy since it is split between 3 groups (although there is a fair bit of crossover) . You've got the archaeologists who want to study coins on context and try and work out how coins were actually used (limited funding though creates problems), the numismatics mob who tend of focus purely on the coins and the collectors who tend to focus on identification and how many different types there are.

Oh and the third group fund the massive plundering of archaeological sites ( Wanborough Temple would be an example that doesn't break the 20 year rule). The result is that coin history is a mess with limited archaeological data being supplemented by large amounts of rather questionable data. Roman coins do better than most due to shear weight of numbers but eh it still isn't pretty.

So dealing with the question coins as ideological countermeasures would probably cover coins minted by usurpers. Carausius, an usurper in britan, would a clear example. After his split with Rome he set up a mint in Londinium (modern london) and minted his own coins.

Revising the image of a public event? Well the FEL TEMP REPARATIO (restoration of happy times) coins issued by Constantius II in 348 were a clear attempt to influence people's view of current events.

Means of campaigning? Late Republic is a bit late for that question but run across that. The closest thing I can think of is some of the coins of the british Tincomarus (a ruler in pre-conquest britian) are pretty clearly made from melted down Denarius

Source: Roman coinage in britian by P. J. Casey provides an overview of roman coinage that reached britian. Info on wanborough can be found at http://traffickingculture.org/case_note/wanborough/