Go to your art store and get "KISS OFF" it looks like a glue stick you can remove the paint off your carpet no matter how old it is. add a tiny bit of water it works on oil too, I have used it on my mattress for when random paint gets on there, and I tried it on my paint shorts too, I just wipe my brushes off on some of my art clothes. and despite the paint being years old it still works.
For cleaning brushes or carpet or pretty much anything else this stuff works wonders, it's also non toxic and you need just a little bit of water. Works with both acrylic and oil, and you can preserve your brushes by letting them dry in the paste you make out of this stuff. When you want to paint with your brushes again, just give it a few flicks and they are good as new.
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