Responsa sur Berakhot 8:9

We are also unsure regarding 'mayim acharonim', the hand-washing at the end of the meal. There are some sages who hold that since we no longer use fine oils¹ to anoint hands during the meal, see Berachot 53b:31, we thus do not need to meticulous about the final hand-washing. I asked [in my dream] regarding this, whether they had anything to rely on in saying so or not.^*Some contemporary sources use similar language but cite the lack of dangerous 'Salt of Sodom' [and not the lack of oil] as the reason not to be meticulous about washing hands (Tosafot on Berakhot 53b:32). See also Rosh on Berakhot 8:6 for a similar argument regarding lack of oils.