This is the first time I am using engine flush. I do small jobs myself rather than giving it to a mechanic. The packaging and delivery were spot on. no leaks in the package. the print on the back says to use it in one go. I decided to experiment and used it in another way. the first foto shows the existing oil which i drained without using flush. it was sooty and dark. Then i added a cheap servo 20w30 1/2 litre and half of the flush , put the engine on idle for 10 mins and drained. expected to see some soot but was totally surprised to see the new oil change its colour to the same one as before. next added the remaining half of both flush and servo oil.idled for 10 mins with some throttle and drained. same situation but the last oil that dripped was a bit lighter than the earlier. Finally filled up with shell ax7 .engine runs smooth now .. need to check after 1000kms or so.