A while ago I realized just emptying the trash on my Mac didn’t actually remove my old confidential project files — they could still be recovered with the right tools. So after a bit of digging and testing, here’s what worked best for me to permanently delete files on Mac after emptying the recycle bin, without messing around too much.
Method 1. The quick way — Dr.Wiper
Here’s how I actually did it step by step with Dr.Wiper to make sure my deleted files were gone for good:
I ran Dr.Wiper’s "File Shredder" feature. It directly overwrites the selected files on the drive, performing a secure erase operation so the data is completely destroyed and can’t be recovered even with advanced recovery tools.
Here’s how I actually did it step by step with Dr.Wiper to make sure my deleted files were gone for good:

(1) Empty the Trash (Finder → Trash → Empty).
(2) Open Dr.Wiper and allow admin permission if asked.
(3) Choose File Shredder on the main screen.
(4) Add the files or folders you want to erase.
(5) Pick 1-pass (Quick) overwrite for fast, secure deletion.
(6) Click Start and wait for the shredding to finish.
That’s the full process I used with Dr.Wiper to safely and permanently delete files on Mac after emptying the recycle bin.
You can also read Apple’s official note about securely erasing disks here:
Erase and reformat a storage device in Disk Utility on Mac - Apple Support
Method 2. The built-in method — Terminal
If you’d rather stick with Apple’s tools, here’s what I did next.
• First check what kind of drive you have:
diskutil info disk0 | grep "Solid State"
If it says “Yes,” you’ve got an SSD; “No” means HDD.
• For HDDs (spinning disks):
sudo diskutil secureErase freespace 1 "/Volumes/Macintosh HD"

That command securely overwrites all free space where deleted files once lived.
• For SSDs or APFS: Apple disables that command (because TRIM and encryption already protect data). In that case, I turned on FileVault following Apple’s guide → Protect data on your Mac with FileVault - Apple Support
Then I filled the remaining free space once using:
dd if=/dev/zero of=~/wipefill bs=16m
When the disk is full, stop it and remove the file:
rm ~/wipefill
That process forces an overwrite of free blocks; combine it with FileVault and your deleted files are practically unrecoverable.
So yeah, those two methods are the only ones that truly worked for me to permanently delete files on Mac after emptying the recycle bin, without having to rely on random third-party apps.