I recently used option 2 successfully (masking tape), after I left my 2 year old briefly unsupervised with the grills off. I'll never make that mistake again!

Unfortunately the metal dome tweeter did not fare as well and I had to replace it. This was over at my in-laws house after just installing their brand new HT, so leaving things dented was simply not an option.

Dan
On-Wall M5HP LCR, QS8 & EP500 in 7.1