i have purchased quite a few of all year sms, and have found a few cameo and high grade coins..ya never know till you open it, but the flip side is on ebay i have seen unopened boxes and envelopes go for 20-50 per set as well...like lottery tickets but you always win (something at least)
Without a postmark on the lip of the envelope there's not really a ton of added value as envelopes can be opened and resealed. I'd open it if it was me.
I voted to keep it sealed, but the quandry you face is perpetuating a mystery if you do. Not opening does you no good unless you try to sell. Trying to sell places the desire to know what the mystery actually is on the buyer, and you could ask for a higher price based on that and let the buyer solve the mystery or not. But I would bet a new buyer would succumb to the temptation and open it. Which brings us to: how much pleasure/satisfaction would you get if you opened it yourself, or do you want to sell that defining moment to someone else? If you keep it…open it and enjoy the euphoria of opening it yourself…imo…Spark
Thanks for all the input. For now I’ve decided to leave it sealed. I’m also going to keep it and at present I’ll probably open it then. it’s not going to hurt or change anything leaving it sealed. I have no current plans to sell if I did open it. Again, thanks for the comments.