There's no way to "clean" them. Trust, I understand the desire, but I'm not sure using pirated plugins on production e-commerce sites is the best idea. If your website gets malware from it, your customer data is at risk along with the business itself.
Some plugins have simple variables to check if you purchased, and you might be able to change it in the plugin editor and get the full features. This won't work for plugins that phone home.
The issue is, that unlike movies, games and others, these plugins are no harder to pirate, but way harder to hide. It's not like a "Yeah, you could get in trouble.", but more like a "If anyone catches you, you are not going to financially recover.", which given the scope of clients (Fam, friends and yourself) and the fact, that these Websites are likely to be on the internet, is incredibly likely. Why not use a free and open source alternative?