Me, I wouldn’t take pesos, simply because I wouldn’t want to go through the hassle of dealing with more than one currency. Not to mention determining if its genuine or counterfeit.
Beaver pelts, now, that’s another story!
It’s actually not that difficult- I managed a retail store in Toronto back in the 1980s. When a customer tendered US currency, we simply used our rate to calculate the CAD equivalent, told the customer what the currency was worth to us, then made change with Canadian money. We would put the money into our night deposit and the next morning the bank would tell us how much CAD went into our account.