Firstly, click here to Play Restaurant City

You'll need:
cheat engine5.5
flash 9/10
piaip tool 1.15

Download piaip tool 1.15:

Rapidshare Mediafire

Steps:

1. Go into Restaurant City and patch it using piaip tool 1.15 (impt: Tick everything except 'no customer wants to go toilet')
   
2. Place as many toilets as you want. The more you put, the faster you get the gold toiletbowl trophy.
3. Remove the cleaner if you have any.
   
4. Scan "F08B0000004F840F"
5. 1 address returned. Right click > Disassemble
6. Change 'je xxxxxxx' to 'jmp xxxxxxx' now all customers WILL use the toilet
7. Just wait till all your toilet bowls are faulty then click them all. Remember, the more toilet you have, the faster you hit gold!

Credits: nameless