Temporarily disabling collisions for a 'from' collider

In my project I have some objects which usually act as ‘from’ objects: their ‘from’ bitmasks are set and they are registered with a CollisionTraverser and CollisionHandlerPusher. I need to sometimes TEMPORARILY deactivate them in the sense that the traverser should stop treating them as ‘from’ colliders. I see two solutions which to me appear identical:
a) remove them from the traverser then add them again later,
b) set their ‘from’ bitmask to zero for a while.

Is either one of these the ‘right’ way to do it, either for performance reasons or conceptually? Is there any difference in the effects of these two methods?