I have two ACNL cartridges and it gets really confusing when I put the wrong game in, so I was wondering if I could mark one of them? Just like a small black dot or something..
I used nail polish to make a small raised dot on the top of one of my ACNL cartridges. It's easy to see which cartridge I have in my 3DS now just by tipping it forward and bit and glancing at the cartridge. And because it's raised, I can run my finger over the dot (or lack of dot) and be able to know which cartridge I have in in the dark.
When I had two copies I put stickers on the back of them. One was blue (main town) and the other pink (second town). I sold the one with the pink sticker on eBay about a year ago and forgot to take it off, haha. Buyer didn't mention it.
Yes you can, my sister used to put gigantic stickers on her cartridges :3
Just don't put anything on the yellow metal bit, that's the part your DS reads the game :0
I usually stick a thin strip of colored tape (washi tape) on top of the cartridges. I like being able to tell which game is currently in the 3DS. Also easy to remove (not that I'd ever resell them though).
This is why I eventually decided to go with nail polish. : D
Sharpie would just fade to a dirty looking smudge on a white cartridge. Nail polish is reasonably difficult to chip off. In the event that I need to unmark my cartridge, I can just use a Q tip with nailpolish remover to get the dot off.
I used a very thin, floral pattern mailing tape to put a piece on the back of my mainly used cartridge so I wouldn't have to load the cartridges over and over to figure out which one I need to use. Though I won't mark them with pen or sharpies just in case I restarted.
I would just worry about the sticker jamming in there...you know how sometimes they get old and the glue melts.
Or if the stickiness got on the inside of the system...
Just saying I understand the concern, I'm way too delicate with my carts too I guess.
The nail polish thing sounds like the best idea though. And I would do it on the edge where once your game is in you can still see it. You wouldn't even have to take the cart in and out to know which one it is.