From a reader:
Our priest and I have recently come into a point of contention. While preparing for the Triduum liturgies, he has denied the use of the crotalus on Maundy Thursday, citing that the General Instruction no longer calls for its use.
As you know, in the Gospel of Mark 16 we read about the handling of snakes. The crotalus is a particularly festive snake, for it has a great rattle (Latin crotalum, a “rattle” or a kind of castanet). Yet… when picking it up and shaking it repeatedly it can become a little testy. This makes for a somewhat agitated liturgy and a steady decline in the number of altar boys.
When handling the crotalus, I suggest brushing up also on the use of liturgical beretta.
An alternative to the crotalus is the… crotalus, a hand-held gadget which has a ratchet within. In Italian it can be known onomotpoetically as a raganella. When rotated it makes a loud ratcheting sound. These are a sound alternative to sometimes less cooperative snake.
Another instrument for this purpose is a thingie with a little wooden hammer which bangs on a piece of wood mounted on a handle. Italians call it a “tric troc”. What that one is called in Latin, I cannot tell.
For Holy Week, the last time bells, or organ, can be rung in the Roman Rite is for the first few words of the Gloria of Holy Thursday. After the beginning of the Gloria there should be no 
bells, which produce such cheery sounds. However, even in the older form of the Roman Rite, there is no clear indication in the rubrics that there should be some other noise-maker to substitute the bells at the elevations and during the procession.
That said, it is a strong and venerable custom that noise-maker such as the crotulus or the “tric troc”, clappers, should be used.
I cannot imagine not using some noise-maker if one is available. The associations of the sounds with the Triduum are deeply part of the way we Catholics do things. They set a wholly different tone during the Triduum.
It seems to me that they should always be used, whether the GIRM mentions them or not. They are not mentioned in the rubrics of the Extraordinary Form either but.. there they are! For centuries used widely in many cultures. Furthermore, this would be a good and easily example of how you might foster that “mutual enrichment” desired by the Holy Father.
And there is always the liturgical beretta.
