A lot of explanations about this matter depend on the fact that the foreign cash could be seen as a foreign assets. They say like "if you export a car and earn 100 yen, then it means that you have now the Japanese assets which are worth \$1 (suppose the exchange rate is 0.01) and this means $1 is invested into those yen money, so this implicitly alludes that the one dollar is flowed outward into Japan.
Okay, I get this so far. But what if I exchange the yen money with dollar at the Japanese bank before I come back to the US? I can see that clearly when I guess at the Japanese side. They got their yen money back into their money market, and it means the supply has been increased. But when I think about this from the view point of US side, well, I just don't get it at all. I went to Japan, sold a product, received yen, exchanged into dollar, and came back; The only things have come back to US are I and the dollar I earned. How can you see this as a dollar outflow?
Or what if I export the car to Zimbabwe where they use US dollar as an official money now? Exporting a car and earning nothing but 1 US dollar, then how come this is the outflow?