The Chess Federation of Canada HANDBOOK (1996 edition)
Supplement 4. Rules for 60-minute and 30-minute Chess
Rule 5. Each player shall handle the clock with the same hand with which he handles his pieces. Exception: it is permitted to perform the castling move by using both hands.
Rule 6. The arbiter should stipulate, at the beginning of the tournament, the direction the clocks are to face and the player with the black pieces shall decide on which side of the board he shall sit.
Rule 7. No player is permitted to cover more or less permanently the button of his own clock with one of his fingers.
Supplement 4. Rules for 60-minute and 30-minute Chess
Rule 5. Each player shall handle the clock with the same hand with which he handles his pieces. Exception: it is permitted to perform the castling move by using both hands.
Rule 6. The arbiter should stipulate, at the beginning of the tournament, the direction the clocks are to face and the player with the black pieces shall decide on which side of the board he shall sit.
Rule 7. No player is permitted to cover more or less permanently the button of his own clock with one of his fingers.