Blu Tack®'s adhesiveness increases over time so take extra care if it's been on there a while. We'd recommend rolling it gently as you can then using what you can get off to dab any remaining bits.

Wipe the affected area with an acetone dampened cloth or nail polish remover containing acetone.

Before applying glue, ensure that all surfaces are of sound nature and clean, dry and free from dust, grease or any other contamination.