Pues, metafóricamente hablando, creo que es... descartar 'lo malo' y no aprovechar 'lo bueno'.

to throw the helve after the hatchet =
echar la soga tras el caldero (= dejar perder lo accesorio, perdido lo principal (DRAE))
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este dicho es una americanización de una expresión alemana: "Das kindt mit dem bad vß schitten" .
A través de los tiempos ha tenido diversas interpretaciones, como se puede ver a continuación. La forma actual empezó a utilizarse en 1936.
En 1846 se decía :"to reject the good with the bad"
En 1941 : "to throw the helve after the hatchet"
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"WOLFGANG MIEDER
"(DON'T) THROW THE BABY OUT WITH THE BATHWATER":
The Americanization of a **German Proverb** and Proverbial Expression*
In memoriam Wayland D. Hand

When the proverb "Don't throw the baby out with the bath water" or its parallel proverbial expression "To throw the baby out with the bath water" appear today in Anglo-American oral communication or in books, magazines, newspapers, **advertisements**or cartoons, hardly anybody would surmise that this common metaphorical phrase is actually of German origin and of relatively recent use in the English language. It had its first written occurrence in Thomas Murner's (1475-1537) versified satirical book Narrenbeschwörung (1512) which contains as its eighty-first short chapter entitled "Das kindt mit dem bad vß schitten" (To throw the baby out with the bath water) a treatise on **fools who by trying to rid themselves of a bad thing succeed in destroying whatever good there was as well**. In seventy-six rhymed lines the proverbial phrase is repeated three times as a folkloric leitmotif, and there is also the first illustration of the expression as a woodcut depicting quite literally a woman who is pouring her baby out with the bath water.1 Murner also cites the phrase repeatedly in later works and this rather frequent use might be an indication that the proverbial expression was already in oral currency towards the end of the fifteenth century in Germany.

What follows is a short historical review of how German-English dictionaries have dealt with rendering the proverbial expression "das Kind mit dem Bade ausschütten" into English:

1846: to reject the good with the bad.7
1849: to throw away the good together with the bad.8
1857: to reject the good with the bad.9
1896: to throw away (or to reject) the good and the bad together, **to use no discrimination**.10
1900: to throw away (or reject) the good with the bad, to act without discrimination.11
1936: throw the child out with the bath-water, hence, act without discretion, reject the good with the bad.12
1941: **to throw the helve after the hatchet**.13
1958: reject the good together with the bad.14
1965: to cast away the good with the bad, to throw out the child with the bath-water.15
1972: to throw out the child with the bath-water.16
1974: to throw out the baby with the bathwater.17
1978: throw out the baby with the bathwater.18
1981: to throw out the baby with the bathwater.19
1982: to throw out the baby with the bathwater.20

As can be seen, it took until 1936 before the English version "throw the child out with the bath-water" appears in a German-English dictionary, using the direct translation of "Kind" to "child". However, this text appears to be but a precise translation without any claim on currency in the English language, since the lexicographer Karl Breul goes on to say and explain "hence, act without discretion, reject the good with the bad." In fact, it was not until the year 1965 that "to throw out the child with the bath-water" is at least given equal footing with the much older but less figurative "to cast away the good with the bad." Starting with 1974 the variant "to throw out the baby with the bathwater" finally appears and with this replacement of the noun "child" with "baby" it has become the standard lexicographical form today."¨
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Un cordial saludo.