How to find locked files

Very often, when I try to immediately delete files in the bin -using option+command+delete- a notification appears saying that the requested deletion could not be finished, because some files were locked, suggesting to identify those files and unlock them.

The problem is that there are thousands of files to identify and this is above my capacities!

Is there a way to do a batch search of these files? Does any community member know how to do it?

I would be most grateful for any help I could receive. Many thanks!