[PD] iemguts canvas delete method

[Jonathan Wilkes via Pd-list]

Hi list,
      Iemguts has an object [canvasdelete] which, when you create it, 
goes in and adds a "delete" method for canvases.  This allows you to 
send a "delete $1 $2 etc." message to a canvas, where "$1 $2 etc." are 
indices of objects you wish to delete from a particular canvas.

In the code I see this comment:

   /* this will crash Pd if the object to be deleted is on the stack
    * workarounds:
    *   - use a clock (see above)
    *   - finally fix this in Pd
    */

1) How do I use a clock?  If the object no longer outputs in zero 
logical time, does that make certain use cases impossible?  (If not 
maybe that's the way to go.)
2) How would you finally fix this in Pd without using a clock?

-Jonathan