There are at least four venues you could explore, I've tried some and they work fine.
1. Sell to your LGS or range. I've sold two handguns to my local range, while I lost about 50% of what I paid for the handguns, I was able to convince myself because the guns will be put to good use and more people will be able to enjoy and appreciate them. It's better than having them sit in my gun safe and do nothing.
2. Sell to companies like Proline Shooters. I believe Proline Shooters do prop guns for movies, and they may offer more than your LGS, though I haven't tried doing it.
3. Sell to professional trappers or wildlife monitoring professional with ATC who will need handguns to protect themselves against wild animals, or other professionals with ATC who will need handguns for professional use only. Note: Sales to ATC holders for personal use it not allowed, and the transfer request will be reviewed by the buyer's provincial CFO so they have the final say.
4. Export to the US if the value of the handgun is worth the fees and hassle.
Aside from these four venues, you could of course surrender your handgun to the local police station (yes, your local police station is where you'd go to do that instead of the RCMP or CFO). Sadly I've actually done this once with my P320 FCU. I stripped everything out of it and sold all the parts, then surrendered the FCU frame to the police so I don't spend more money on P320 builds. I've literally done at least half a dozen builds and think it's about time to move on. Given the current reputation of SIG in general and P320 in particular, this may not be such a bad move after all.
Lastly, if you have friends and family close to you and that you trust, and if one of them is interested in handguns but never got into the hobby because of the freeze, you could lend the handgun to him/her by initiating a lending ATT application via the CFO. Once approved, the borrower of the firearm will get the handgun from the lender and be the legal keeper of the handgun for the validity period of the ATT. I personally do not recommend this because there's more legal nuances involved and you need to REALLY TRUST this individual to take care of your handgun.
Food for thought
PJ