I have some ALW Flex resin and find it “gooey” sort of like Karo Syrup. Doesn’t clean well with IPA, you have to use ethyl alcohol and even with that it’s a job.
I was mixing it 1 to 2 with Grey ALW resin but still found it hard to clean. I was looking for a bit of flex in my prints. I now add about 10% Flex to the Grey. It helps some but also helps to use it up.
Be sure to mix it well both before using and also before and after adding to another resin.