I was wondering why cannot boiling chips be reused.

As far as I know, they are microporous materials, often coated with PTFE.

They work by, I suppose, giving the heated substance a small cavity, in which a phase transition is favored.

Yet, the golden rule of boiling chips is: they cannot be reused.

I was wondering why they cannot be treated the way dessiccant materials (for instance, molecular sieves) are used, for instance by washing them after use and driying them in oven (especially when non-dangerous materials are involved).

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    $\begingroup$ Of course it depends on the use case. Will traces of compounds from the previous use interfere with your requirements for purity in their next usage? Will the chips become coated with some compound from the first usage that interferes with its function as a boiling chip in the following usage? If these things don't apply to your use case, and they appear to be doing their job, then I don't see why they couldn't be used more than once. I have done so on many occasions. Though I don't think I've ever used PTFE coated boiling chips; it seems like that would get in the way of their functionality. $\endgroup$ – airhuff Jan 28 '17 at 1:18
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    $\begingroup$ You couldn't coat the chips with PTFE without sealing the pores. That would destroy their functionality. $\endgroup$ – MaxW Jan 28 '17 at 2:08

According to this post at www.reference.com/science

Boiling chips are generally porous, trapping heating bubbles and allowing solvent vapors to form in the air cavities. They should always be added to a solvent prior to the beginning of a heating cycle; adding to a hot liquid may cause it to violently boil over. Boiling chips and stones are only used once, as the absorptive material becomes impregnated with the first solvent used in.

And Wikipedia confirms the basic idea of why they shouldn't be used more than once:

The structure of a boiling chip traps liquid while in use, meaning that they cannot be re-used in laboratory setups.

From personal experience however, I have to disagree with these absolute "cannot be done" sort of statements. I used to rinse the used chips in an appropriate solvent and then heat them at some temperature well above the solvent's boiling point overnight and don't remember ever having problems.

I realize that the boiling point isn't completely relevant when you can have porous, high surface area material with adsorbed solvent. Also, as I stated in the comments, I don't remember using PTFE coated chips.

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    $\begingroup$ Boiling chips are cheap unless you're using some really exotic type. You'd spend more money on the solvent in which you rinsed them than they are worth. // Having said that, I'd agree that baking them in an oven at a temperature sufficiently above the BP of the solvent should rejuvenate them. $\endgroup$ – MaxW Jan 28 '17 at 2:13

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