How to transfer dataframe to list and not include NA value ? Thanks!

There is dataframe ori_df

library(tidyverse)
ori_df <- data.frame(category=c('a','b',NA),subcategory=c('w',NA,'Z'))

Below code can transfer ori_df to list fin_list,but the result include NA

fin_list <- as.list(ori_df)

How to delete NA value in fin_list , the wished result as below fin_list_wished ?

fin_list_wished <- list(category=c('a','b'),subcategory=c('w','Z'))