I just went through this with Computershare.
We had the paper certificates ourselves but, couldn't find them anymore. I contacted Computershare and they put a hold/freeze on the original certificates. I then will get new certificates generated for me. There is a charge of +$100 for this.
Why in the world would you want to hold paper certificates (and pay for the 'privilege'!)?
You've already demonstrated one problem, you can misplace them.
Do your heir/executors a favor, and get them converted to electronic and hold them in a brokerage account. I had to deal with my FIL's paper stocks when he passed, plus some held at the transfer agent. It was a fair amount of additional work, two different transfer agents to deal with, plus dragging my MIL to a Fidelity B&M office to get them all converted, which was complicated by the fact that we had to get things converted to his new EIN (in place of SSN) before we could do anything.
It would have been a lot harder if I hadn't done a fair amount of research to figure out how to do it. Several sites had you mailing them in, and insuring them, all of which adds time/$ to the process. It all requires a Medallion signature, which can be difficult to obtain (Fidelity accommodated us, as they were receiving them, and we were there in person). Basically, the Medallion signature has them on the hook for the transaction, not just identifying that you are who you say you are.
I don't recall if there were any fees involved at all, maybe some minor ones at the transfer agent (like single digit $ per stock - something small if anything).
-ERD50