Does beer help to flush thc out of your system?

No: THC and alcohol are two distinct chemicals. Using one or the other does not affect the blood levels.

NO: there is nothing that really increases the excretion of THC, despite a lot of hype on internet-sold products. What large amounts of liquid will do is dilute your urine, which may bring the amount of THC per cc down below detection levels, but modern testing looks for excessive dilution and flags that sample as suspect. If you are smoking weed and being tested, consider that a problem and STOP.

No: There are no flush agents, regardless of what you read on the net. If you are a light uses it may be below detectable levels in a few days on a pee test. In heavy or chronic users it can stay around for a month or more.