Using a pair of small needle nose pliers, gently pull the "mixing thingie" out of the nozzle barrel. Drop the "mixing thingie" into a small jar of laquer thinner or acetone.
Clean the inside of the nozzle barrel with a Q-Tip and laquer thinner or acetone. When the "mixing thingie" is clean, dry the parts and re-assemble.
Pretty simple and easy.

Alternatively, put the nozzle into a plastic bag and keep it in the kitchen freezer for later re-use. Zero temperatures keep the adhesive from setting up.

I prefer cleaning it out.

It is best to have some Hysol on the faying surfaces, with a small fillet around the bonded edges of the parts to "trap them".

Clean-up is easily accomplished with laquer thinner, acetone, or rubbing (isopropyl) alcohol from your local Chemist.
I think that if you get it on your clothes, you are hosed.

Harley Condra
BVM REP
JetCat REP