I love Sharpies. I have just about every size that they make. I have 1 in my knitting bag, I have 1 in my camera bag and I have a complete color set in my desk at work. I use them for marking my film as I use the rolls so I know what they are when I get the film developed. I mark my knitting labels with the project for which I bought the yarn. But, Sharpies aren’t as permanent as they might suggest they are. The ink can be rubbed off of plastic or certain glossy surfaces.
The ink from Sharpies can be removed from non-porous surfaces such as wall, plastic, etc. Just use alcohol. Rubbing alcohol that is. It might take a couple of passes but it will come off. If you get the ink on cloth, concrete, stone, wood, sponge, anything porous, it is as permanent as the earth. It’s not going to be removed. Faded – eventually, but not gone. Trust me, I exploded on on a dress, which is now a rag.