The ATO send an auditor to a synagogue.

The auditor is doing all the checks and then turns to the Rabbi, and says, "I noticed that you buy a lot of candles."
"Yes," answered the Rabbi.
"Well, Rabbi, what do you do with the candle drippings?" he asked.
"A good question," noted the Rabbi.
"We actually save them up and when we have enough, we send them back to the candle maker and every now and then, they send us a free box of candles."
"Oh," replied the auditor somewhat disappointed that his unusual question actually had a practical answer.
So he thought he'd go on, in his obnoxious way...

"Rabbi, what about all these matzo purchases? What do you do with the crumbs from the matzo?"
"Ah, yes," replied the Rabbi calmly, "We actually collect up all the crumbs from the matzo and when we have enough, we send them in a box back to the manufacturer and every now and then, they send a box of matzo balls."
"Oh," replied the auditor, thinking hard how to fluster the Rabbi.

"Well, Rabbi," he went on "what do you do with all the foreskins from the circumcisions?"
"Yes, here too, we do not waste," answered the Rabbi.
"What we do is save up all the foreskins, and when we have enough we actually send them to The Tax Office"
"Tax Office?," questioned the auditor in disbelief.
"Ah, yes," replied the Rabbi, "Tax Office ... and about once a year, they send us a little prick like you"