Yes, same here. I couldn't possibly just delete them all wholesale, even if it was possible. There are some old gems in there - some of them predate my joining Mudcat and I didn't know of their existence till somebody refreshed them - things like the "Why We Sing" threads are priceless, and I would hate to lose them.
Having said that, I shudder to think how many threads I have traced now, and some culling is needed. It will be a slow process though, as I check them to find out if they are worth keeping and get sucked into re-reading the good ones!