Cash exchange

I'm an ex-Nova teacher that is running out of liquid income. I'm lucky that I have a decent amount of cash on hand. The problem is it's in American currency (bills). What or where is the easiest way to convert this into yen? I'm close to the Kansai airport, should I just head there and take the garbage exchange rate? Is there a way I can take some cash to the post office and buy a ''postal money order'' and then go to another post office and cash it? If so who would I make it out to? Myself? Cash? Will they exchange it at the post office (I've never done this) or do I need to go some place else?
I just need some cash. What should I do?

Was that the big language school that went out of business?

It was in all the papers. Teachers were giving lessons for food. I feel for them.

Are you really close to Kansai airport? Then you might as well head for the airport. But if you are in central Osaka, try Travelex money changer - at between Central North Entrance and Central Entrance at JR Osaka station. Or if you see a branch of Bank of Tokyo MItsubishi near where you live, go in and ask if they exchange foreign currency or for their nearest branch where they do.

Other options include local banks and post offices. I have done exchanges at both before but whether or not they can do it depends on the particular branch. The post office tends to have the best rates so I would try there first.

Currency exchange of cash is a fairly straightforward process. The post office will just exchange it to yen for you, there is no need to convert it to a money order or anything like that. Tokyo Mitsubishi should also do this for you, and if you have a Shinsei or Citibank nearby they definitely will.