The OP could donate them:

https://www.aeroplan.com/en/collect/..._donations.jsp

"Through Aeroplan's first partnership with Engineers Without Borders, support projects that improve lives through technology, bringing clean water, sustainable energy and food conservation techniques to communities in need overseas—and educational hands-on seminars to Canadian high schools.

OR

Donate your Aeroplan Miles to Air Canada's Kids' Horizons

Via Kids' Horizons, Air Canada's charitable support program, improve the quality of life of the youth and their families. "

My kids had about 10K miles in their accounts from some paid travel a few years ago. Since they travel on reward tickets now, I donated their miles, rather than have them sit collecting dust.