When notes are in circulation, it's always a good idea to take up GEM UNC notes and put them somewhere well protected rather than putting your money in a savings account.
Although the 20's are too common, book value for UNC will hit $25 and $30 for GEM UNC. You could then sell them to the States (on eBay) for $22-25 each, a sweet 10-25% return. The 5's and 10's GEM UNC will pick up value faster (proportional to face value) as new notes come out.
It's very simple actually:
Put up a GEM UNC $5 on eBay, charge $0.50 more on shipping than it cost you. If you can sell one note for $5 US (it's usually more), you'll make 30% return, less eBay fees. Do not accept PayPal unless you sell them for a bit more. More efficient if you do it with bricks of 100 notes. 100 $5 bills will go for $500 US (or more) as there is always potential to sell them piece by piece for just a little bit more.
Look at the 1991 20's. They were so common. Now the GEM UNC's are almost tripled in face value. Wish I had taken up a whole bunch when I was a lil boy.