Q. If someone forgot or misplaced a Shalach Monnos, can it be send after Purim?
A. HoravYaakov Hirschman Shlit’a mentioned that although one cannot comply with the mitzvos of Purim after it has passed, there is still a benefit of Havoas Sholom between people and other mitzvos involved, when delivering the Shalach Monos.
Horav Shlomo Miller’s opinion is similar.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a