You clear a betting bonus by wagering the bonus (rollover) a set number of times. For example, if you have aR$1,000 bonus and you need to wager it 5x, then you will have to placeR$5,000 worth of bets within the sportsbook to clear it in full.
roll sth over\n\n to move a debt or loan from one company to another, or to make a debt or loan arrangement continue for a longer period than previously agreed: Most government debt as it matures is rolled over. (Definition of roll sth over from the Cambridge Business English Dictionary Cambridge University Press)