What do you mean by cleaning??
I say this with all seriousness...some folks consider a good cleaning to be running a few patches thru the bore.
When I talk about cleaning a Marlin 60, I'm referring to a simple strip.
You remove the barreled action from the stock,
then remove the four screws or two plastic retainers,
and pull the action out or the action housing.
You then gently remove the bolt, recoil spring & retaining rod from the action.
Then take a toothbrush & your favorite gun cleaner (that doesn't harm plastic)
and get to work scrubbing the daylights out of it.
The chrome parts should be sparkly and the blued stuff should be rust-free/grit-free/grime-free.
Break out 000 or 0000 steel wool or fine-grit (600+) sandpaper if/when needed.
Wipe all leftover steel wool hairs or sanding grit off/out.
You then put a SINGLE DROP of gun oil on your finger & rub it all over the action.
Do the same with the bolt & inner action housing. No more, no less.
That's a simple cleaning...
While it's all there for you to look at, take some nice clear pics & inspect everything.
Then GO TEST IT...it might have resolved your issue.
If it's over 20 years old, it's usually Spring Replacement Time.
Replace the Recoil spring & others with a JB Spring kit.
Replace the buffer.
Replace the hammer spring.
Replace the magazine spring (Numrich or Marlin or Brownell's)
They're all pretty inexpensive, and well worth it, because you're gonna get at least 20 years out of 'em.
For those four operations, refer to Arrowdodger's Model 60 Breakdown. ArrowDodger's Model 60 Power Point Presentation.. or Here if you don't have Powerpoint on your computer
Model 60 action assembly - RimfireCentral.com Forums
Oh yeah, take a pic of that dimple you were talking about while the action is out & post it here.
We need to take a look at that.
Oh, make sure the Ejector spring is in the right position, that little rascal can cause all sortsa problems.
Again, use Arrowdodger's post or my Marlin FTE thread here on G&G.