For yrs I used Lee`s 2 holers & still do at times !!
I found that smoking the mold was just a band aid for other minor machining problems , but there still a deal for under $20.00 bucks & even $39.00 for a 6 banger !!!
Here`s what I would do with your mold , first clean it throughly with Mean Green it will not hurt the mold .
Second lube litely the V & pins & cast a bit to see if the problem still exsists.
If it does let it cool completely , when cool take a bullet & drill a hole the size ya need for a small bolt or screw to go into deep enuff to hold securely.
Get ya some powdered COMET cleaner make a paste & coat the bullet enuff with the paste then place it into the mold & spin it with a cordless drill.
The commet is a mild abrasive so cleaning & reapplying a couple of times should be all it`ll take , it`ll do a deep cleaning & remove burrs . If done enuff it actually enlarge the mold & take the sharp corners off so check often!!