It’s easy to make an all-purpose solvent cleaner that will remove paint and inks.
Go to the hardware store and buy some paint thinners (xylene), acetone, and metho. Mix it in the ratio 5 parts xylene, 3 parts acetone and 2 parts metho.
That’s the basic formula of this remarkable product that unfortunately isn’t available in Australia:
Now, because this is very volatile (evaporates easily) and aggessive towards plastics, you need to store it in a metal container, such as a 5 litre lawnmower fuel can. When you wish to use it, you could just swab it with a rag, or transfer some to a generic trigger spray bottle. But if you do that, tip the remains back into the fuel can when you’ve finished, as it will probably destroy the trigger mechanism.
With inks, it should dissolve straight away. With paints, squirt it on and leave it for half an hour or so, and the paint should bubble up and peel away from the surface.
You may find that if you’ve used it indoors (on carpet, for example) there’ll be a solvent smell, due to the xylene. It’s not toxic, but if you want to get rid of it, blast it with a hairdryer for a few minutes to evaporate it.