Need advice on how to clean some stubborn resin

Hey guys, this may sound like a stupid question, but I just can't seem to get the black specks off of the bottom of my stemless matrix perc tube. The black specks are on top and below of the perc and in the base of the stemless portion.

I normally use 420 cleaner and it cleans the rest of my tube just fine but doesnt seem to touch the resin that has seemed to settle on the base.

Any ideas on what could get rid of this shit? even soaking overnight in 420 cleaner doesnt do anything.

Thanks,

99%alcohol and kosher salt allways worked for me..sterelizes your glass also..

BUMP
I clean my pipes and bongs with alcohol and salt, also.
The alcohol is the cleaning agent, and the salt is the scrubbing agent.
Put the alcohol in the dirty area, then add salt.. then shake it.
Might have to repeat a few times but this seems to work well for me.

i agree, alcohol and salt. although i used epsom salt. sometimes i crushed it up to get into parts of my glass that the bigger chunks couldnt.

yea i keep it simple,kosher works,if there is a crevice i cant get to,i use iodized table salt..cleans the perc tubes easily!