See the latest answer to this question here: https://docs.julialang.org/en/v1/manual/faq/#How-do-I-delete-an-object-in-memory%3F
Retrieved from the docs:
Julia does not have an analog of MATLAB’s clear function; once a name
is defined in a Julia session (technically, in module Main), it is
always present.If memory usage is your concern, you can always replace objects with
ones that consume less memory. For example, if A is a gigabyte-sized
array that you no longer need, you can free the memory with A = 0. The
memory will be released the next time the garbage collector runs; you
can force this to happen with gc().