Custom instructions and Memory

I have a task in progress that requires processing a lot of data and organizing it, so I told ChatGPT how to read the data and to remember how I defined and processed it.

As a result, the task itself is working very well so far, but I had to delete some private information that I had stored in memory.

It still seems like I need to add some complex definitions, and I’m running out of memory.

Can I use custom instructions as an alternative to memory? If I tell ChatGPT to write out the contents of memory, copy them to custom instructions, and then delete them from memory, will ChatGPT use the rules moved to custom instructions in the same way as they were in memory?