I need to refasten an aluminum splash shield to the bottom of my
aluminum shower door. Previous screws were steel, I guess, and rusted
out. What shall I use to minimize galvanic action? I haven't seen
aluminum sheet-metal screws around.

***
Ivan,

Use good quality aluminum pop rivets. They will not react galvanically with
the aluminum doors.

DO NOT USE stainless rivets or screws as they will galvanically react with
the aluminum doors and corrode the aluminum out.

Larry