Originally Posted by
slyman
well I don't think I want to punch through it, if it's fine, idk about after that.
The point is, if you could poke a hole through it, it's way too far gone to be ridden. If you can't poke a hole through it with a pick, that means you still have solid steel there.
I would definitely ride that if there is sentimental value there. The top tube area is not super high stressed like the bottom bracket area, or fragile like the seat stay/seat tube junction. I doubt anything bad is going to happen. Just ride it.

^ don't do that though