[Leica] selling used camera gear from Canada to USA

[bladman99 at yahoo.ca (Dan C)]

I am in the process of selling a lens to someone living in the USA.  I live
in Canada.   Are there issues of custom's duty etc. that I should be aware
of?   If I ship the lens from an address within the US, would that solve
that problem?   If the buyer decides to return the lens and ship it back to
me in Canada,   is there a risk that I may be facing Custom's Duty on the
return of the lens?

-dan c.