Good luck. It sounds like the paint has already dried. Try taking a cloth put it over the painted area and melting the paint. Then immediately take dry soap powder and rub it in. You might have to do this a few time.
Probably the easiest way would be to use paint thinner type wash on them. I would just take them down and try rubbing out the paint with a rag soaked in paint thinner.
Paint is very thick and often in bright colors. It can be knotty to deal with and will possibly bleed through if you try to wrap it. You don't fairly remove them in the sense you are design Cleaners and such aren't going to do the deception This is what found worked when getting rid of old feeling
paint can be removed by leamon juice. take two or three lemon, cut the leamon and rub the juice in the area paint, after that clean the curtain with water.