It's only dumb if:
a. it actually works, or would actually work if cleaned.
b. it's within warranty.
Otherwise, it's this or turn it into a paperweight.
If it's broken, the average price of a broken Xbox 360 on Ebay isn't even $10. So the real determination of if this was stupid boils down to how much the window repair will cost compared to how great the feeling of throwing that Xbox and seeing something break felt.