In the following game (game 11 of his 1961 World Championship return match against Tahl) he demonstrates how to play with Rooks against Bishops of opposite colors. Just about everybody knows the rule of thumb that B of opposite color endings are almost always drawn. In many positions even an extra P isn't enough to win if B's of opposite colors are the only pieces on the board.
But, the presence of R's usually makes a lot of difference and gives the superior side winning chances. If all four R's are on the board the game actually has more characteristics of a middlegame and so makes the R's more effective. The reason is because the more aggressive B can combine with the R's (or sometimes it's the Q) to attack some target or establish control over the squares of its own color. So, it can often win in positions that would otherwise be drawn if B's only would lead to a draw. This is what Botvinnik demonstrates in the following game.