Welcome to the forum.
I'm assuming it's an aerosol stencil? Again depends on the area of coverage, thickness and type of paint, etc. Got any pictures?
Best approach is always to start on inconspicuous area to see there's no reaction with the paint if you're using solvents and you don't make matters worse.
You can clean PVC tubes prior to repairing in order to degrease with Polymarine 2903 Solvent Primer (contains MEK), but the danger is you drag the paint onto the surrounding tube material, as this can actually soften the PVC surface.
You might be better to use a little acetone (nail polish remover) to see if that has any effect. I'd also be tempted to see if some of the paint could be scraped off using a Stanley blade on the flat cutting edge surface dragged backwards so it can't cut to see if that works. Tube pressure needs to be spot on if you're attempting this.
Once the majority of the paint is removed - use a green scourer pad and well lubricate with detergent or TFR and thoroughly wash and rinse the area.
If you're using any solvents - ensure you wear gloves and work in a well ventilated area.
Sula
