In yesterday’s Daf Yomi, Bava Batra, Moo amud bet, there is a surprising mnemonic, עמלק סימן. That is, the four cases under discussion in the following section are arev (guarantor), malveh (lender), lokeach rishon (first purchaser) and qablan (a different type of guarantor), who may or may not testify on behalf of a certain other party as to ownership of a field. The letters spell out Amalek.
This is surprising, to use Amalek as a mnemonic, when we are supposed to blot out the memory of Amalek. And Hagahot Yaavetz (Rav Yaakov Emden) has an explanation about how it is OK to use it to remember Torah, and how there is a tipcha (disjunctive accent) on the lo of lo tishkash, לֹ֖א תִּשְׁכָּֽח , somehow telling us that it is sometimes OK for the sake of not forgetting.
The Masoret HaShas, besides pointing us to the Hagahot Yaavetz, points out that the Dikdukei Soferim notes that in many kitvei yad, this mnemonic isn’t present.
Thus, for example, we don’t find it in Ktav Yad Firenze, Paris, or Vatican.
Ktav Yad Vatican
If so, perhaps we should cross out this siman, this zecher, from our gemaras. In this way, we can literally fulfill the positive command of תִּמְחֶה֙ אֶת־זֵ֣כֶר עֲמָלֵ֔ק.