... with opening polyethylene cans

 
turn off the cap closing,
done best with a ring wrench
------->>
turn cap
till guarantee ring breaks away
<<--------
remove guarantee ring and cap closing
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if available screw tap on the opening
<<--------

open or close the canister with red discharge port
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upend the canister so the lever tap is situated on
the bottom, then turn the discharge port to retain liquid.
<<--------

after retaining the liquid lock the canister
and store it upright
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