Help with confusing taper

I have a friend who I’m helping who is on .5mg of clonazepam. They have 2mg pills they are cutting from.  They want to do a liquid/water taper.  When I did mine I did the 300ml water taper and it worked well. It took me over 2 years to taper 2mg. 

Question is what’s the best way to water taper the remaining .5mg out of a 2mg pill?  Also can they use less water than I did since it’s .5mg left.?

Also.  They are allergic to cold liquids. When I did mine I kept in fridge. Can they keep out? For how long?  Thank you for any help!!