Q: Gray layer on MagSafe port

There may be an interrelation with damages to the port (in MacBook/Pro)

and the inability for the MagSafe connector to power the computer.

A cure may be to inquire about the cost of replacement, of the MagSafe DC-in Board.

This may be more complex or may require a bit more technical effort for casual users

to attempt a repair replacement of this part; or to diagnose then get the correct part.

This part is referenced in the iFixit.com repair guides for macbook/pro, online.

https://www.ifixit.com/Device/MacBook_Pro_15%22_Unibody  - 15-inch 2009

• Mac notebooks: Using and maintaining your Apple MagSafe Adapter - Apple Support

• Apple Portables: Troubleshooting MagSafe adapters - Apple Support

• About Mac notebook batteries - Apple Support

The cure would appear to be, replace the MagSafe port assembly in the computer.

You could get free advice or diagnostic help from an Apple Store with Genius staff

with an appointment; however the unit is probably too old for them to offer repairs.

• Make an appointment at an Apple Retail Store Genius Bar
• Find an Apple Authorized Service Provider

In any event...

Good luck & happy computing!