A pressure washer might work, but runs the (likely) risk of also blasting out details you wanted to retain. Still, if you're going to start again anyway it's worth trying first.
A cotton bud and some emulsion remover might do the trick, but it's quite hard to remove only what you don't want.
Depending on how small the specks are, the ink might just fill up behind them. It's at least worth a test print to see what happens. If nothing else it'll give you a better idea of what works and what doesn't. Nothing beats direct experience.
Not always necessary, but preferable.
