That's about the safest way to do it. As long as you have a low-overhead, potentially high-profit business and aren't bringing in too much money from the illegal activities, you can do it this way. If you need to launder LOTS of money, you'll need a *friend* at a bank. One thing you can do is go to the bank, take out a loan for, say $1 mil. For loan collateral, you put up, say $1.2 mil in cash. You default on the loan, the bank keeps the cash, and you still have your, now legal, $1 million loan.
There are lots of other ways too. It mostly depends on the amount you need to rinse.