How does the next paragraph end?

How to preserve leaves and flowers
Buy a fresh new can of clear polyester casting resin.
A container that has previously been opened may be difficult to open if the cap/lid is sealed tight with resin exposed to air.
Find out the date the can was bottled because resin has a short shelf life; even in sealed, airtight containers, it can become too viscous to effectively coat foliage and flowers.
Check the viscosity of the resin fluid. Set up in an open-air area with plenty of ventilation and away from open flames.