I can definitely relate to the cleaning frenzy! It happens to me too - often it's really intense in the fall. But it can hit any time and I think the best time to do it is when the mood strikes, otherwise it is often more frustrating than anything.
As for craft/stamp/scrap room purging, I am a huge advocate. It's worked exceedingly well for me. My stamping and art project interests have fluctuated a lot in the last several years and many products were more of a hindrance than a help.
I have a "dead corner" in the closet where most of my supplies are kept - a spot that's hard to reach and I tend to store things in there. Presently it is stacked up at least 5 feet high with everything I am going to sell. My latest purge a couple of weeks ago includes paper, dies, stamps, tools, markers.... a ton of items that I will sell at an LSS customer yard sale. In the past, my sales have yielded $300+, and I don't think I even had as much then.
I've done mini-purges in the past and sent unloved stamps and embellishments to friends, but now I've really narrowed my supplies down to what I like to use the most. I don't have too much that's "what was I thinking?!" but my focus has shifted from heavily (my version) embellished cards to something a little more simple but with little touches, and I'm working on more art projects and illustration work in addition to making cards for fun. So unless my focus shifts dramatically again, I think I've finally settled in to a comfort level with the quantity and types of products I have.
I really think having too much does get me bogged down and I hope you feel refreshed and inspired when you are done! Also, going through your supplies can be inspiring. Not just seeing what you have that may have been lost in the shuffle, but reorganizing too. I love to reorganize and often just keeping things in different places gives me fresh eyes.
I'd suggest that you have a "not sure" box too. You're less likely to have regrets if you don't toss too impulsively. Some things, you'll know instantly; but there may be items that you can't quite make up your mind on yet. I will sometimes turn to my "not sure" box and if it doesn't "click," I toss/sell.
Good luck (sorry so long-winded!) and I hope your purge goes well! Please come back and let us know how it's going