Many of the discs i find what looks to be like a spec of dust on the writing surface

I have multiple 25-pack DVD-R Verbatim spindles and before burning i check the bottom of the discs for anything out of the ordinary.On many of the discs i find what looks to be like a spec of dust on the writing surface so naturally i try to clean it off, but it doesn’t come off!, it’s seemingly stuck in the dye.
I burn anyway and the process finishes with no problems.
Transfer rate test finishes with a smooth graph and no spikes.
I go on to the disc quality test and sometimes the test freezes before it reaches 10% so i redo the process.On the most recent disc i got a disc quality of 90, no major spikes and what seems to be a decent burn:

General Information
Drive: TSSTcorpCD/DVDW SH-S182M
Firmware: SB03
Disc: DVD-R (MCC 03RG20 )
Selected speed: Maximum
PI errors
Maximum: 23
Average: 3.81
Total: 38682
PI failures
Maximum: 4
Average: 0.14
Total: 1798
PO failures: n/a
Jitter: n/a
Scanning Statistics
Elapsed time: 6:46
Number of samples: 129396
Average scanning interval: 1.09 ECC
Glitches removed: 0

Does this mean i shouldnt worry about the little specs?

It’s a bit hard to say without posting the full graphs. If there is a problem with something sticking to the dye surface, then it should appear at roughly the same point in the graph.

I did the quality test again and it froze twice before reaching 100% on the third try, why is it doing this?..
The third time i got a big spike near the end of the disc and an extra (5 total) PI failures.
The result is worst than yesterdays, i didnt touch this disc since the first time i did the test so why did it get a worst score today?!
Regardless of the scores, what could the little specs that i’m seeing on the discs be?