I've not worked with a lot of Meranti.
I have worked with some resinous Spruce. I used generous amounts of pure Acetone on a cloth / applicator to spot treat the resin pockets and around knots before applying the sanding sealer.
Leave it a few hours or overnight and treat again to make sure.
Acetone is a very safe and environmentally friendly solvent provided you are aware of the following:
- Flammability
- If used in a confirmed space you could become intoxicated and unsure on your feet - happens sooner than you think.
- It is a carrier - so if you dissolve something harmful into it, it can take it through your skin very quickly
- It can break through most gloves very quickly
I make an applicator using a 1" diameter dowel with a channel rasped all the way around at 3/4" from the end.Put some cotton wool on the base ( round cotton wool piece are sold under the everyday value range in Tesco quite cheaply for makeup removal ) , a piece of bedsheet cloth over that and cable tie the ends of the cloth into the rasped channel. This can be used to scrub at the resinous areas without coming into contact with the solvent with your hands. When finished, snip the cable tie and throw the pad outside in bin ( not indoors ).