I started by putting every last piece of makeup that I own (including all the random lip products in my purse) into this basket and taking it downstairs, away from my makeup area. There was a specific reason that I wanted to move everything away from there. Sometimes when I go through my makeup one drawer at a time, I'm more likely to keep products I don't enjoy that much just because I sort of have a mind set that I can keep it if there is room in that drawer of my stash. Changing locations eliminated that excuse.
Next, I went through my lip products and quickly sorted into different bins. I tried to only take two to three seconds to decide on each product to either Keep, Maybe, or Toss.
Maybe: Items that need further thought.
Toss: Items that are old, gross and need thrown away. For example, I had a lot of pretty old Essence lip glosses that had separated and were disgusting and I was afraid to use them.
That yellow line in the top is where the product has separated out. Ew! These glosses were the entire reason I decided to do this declutter.
After the initial sort, I went back and did a second, more thoughtful sort of the Maybe bin, swatching if need be. Anything I still couldn't decide for sure on got put into one drawer in my makeup area which I am designating as "Makeup Purgatory". I'll leave it there for a month or so and any products that I miss and reach for can be added back into the main collection. At the end of the month, anything I haven't reached for can then be tossed or donated to friends. I also do this sort of thing when I purge my closet as well.
After finishing all the lip products, I did the same with the other products, by category. This is what I ended up setting aside for "Makeup Purgatory".