I'll say if you are 'new' to this, then your boss might have just found the first busy task he knew
had to be done. I'd start the next day and first chance you get (without just busting down the door) ask the boss "How long should this take?", if he doesn't know, offer an estimate, and see if he drops his coffee. If he says XX hours, and you expect it to take that long, get back to it. The third possibility is that he is testing your patience/resolve, and by showing the initiative to question the task at hand, he may have a chuckle and tell you where the replacement one is.
You could always try some Cooley Magic, made for stripping whether resistant ink off of awnings for gods sake...
https://www.reecesupply.com/2320143/Product/Cooley_Cooley_Magic