I'm thinking of wiping off my friends glasses with concentrated liquefied ghost pepper.
I don't believe you're actually serious. Are you seriously planning on putting ghost pepper on your friend's glasses?
Haha. Don't worry I'm just joking. I only thought about it but Nothing crazy like that would happen.
Your friend's glasses belongs to them, and not yours, so I don't think it's ever going to be right for you to put in ghost pepper on those glasses. Furthermore, you would be endangering their health and can get very harmed with the ghost pepper having contact to their eyes, as it can burn them. Why not just play harmless pranks with them, if you really wanted to prank them?
I didn't think about the health risk part. My friend always says that he doesn't care about his glasses so it'll be alright.
He may not care, but that doesn't make it right that you are planning on putting ghost pepper on there, as his eyes will turn red and it will burn, and possibly blind him temporarily. I know you're not actually going to do it, but you should not even think about doing it in the first place, as what you should be planning is how to be a better friend and be supportive with him.