Editing large amounts of data

I have a very large (30,000+ rows) spreadsheet that someone else filled out, and I am attempting to use some of the data, but it is not formatted consistently. One of the columns is zip codes, and half of them are shortened (92104) and the other half are extended (92104-4515). Also, bizarrely, the person who filled it out put a ' before the extended zip codes, so it looks like this: '92104-4515 in the formula bar, but does not show up in the cell. (They actually did that for every cell in the spreadsheet, I have no idea why.)

Is there any way to easily convert the extended zip codes to the shortened ones?

I have attached a spreadsheet, in case that will help.

Thank you so much!