I have a pruning set from amazon (link included at the bottom). I cut right where the leaf meets the stem because usually monstera grow from the stalk of the newest leaf, so you usually want to keep that part. Once the new leaf grew in I got rid of the old stems (which started to yellow once the new leaf grew). I always sterilize my shears with hydrogen peroxide before and after I use them.
Pruning Shears, ZOUTOG Stainless Steel Garden Shears,3 Pack Gardening Gifts Including Garden Clippers, Gardening Gloves - for Garden Trimming,Tree Trimming, Weeding and Transplanting https://www.amazon.com/dp/B07ZVQR29L/ref=cm_sw_r_cp_api_i_mlfwFbZR22JCJ