One of the perks of this method is that charcoal is a natural and relatively cheap substance
The answer is yes you can

A German-language leaflet with instructions, warnings, and contact info must be included Prohibited designs and claims Phrases like harmless, healthy, tar-free, detox, natural, medical Images of fruits, desserts, toys, cartoons Packaging that resembles food (e.g., candy bags, juice boxes) Implied health benefits or smoking cessation claims Information Leaflet Requirements Each e-cigarette and refill container sold in Germany must include a leaflet containing the following information: Clear instructions for proper use and storage Contraindications, including health conditions under which use is not advised Warnings stating that the product is not intended for non-smokers, and its use or distribution to children and young people is prohibited A list of possible adverse health effects or side effects Information on the addictive properties of the product, particularly if it contains nicotine Toxicological data, particularly regarding inhalation Full contact details of the manufacturer, importer, or a responsible legal or natural person within the EU Tax stamp placement Packaging must reserve space for the German tax stamp (Stempelmarke) Should be placed on the seal or top without obscuring warnings or product info Environmental labeling (VerpackG requirements) All packaging must be registered in the LUCID system Label must include recyclable symbol (e.g., Der Grne Punkt) Use of separable, recyclable materials is recommended How to Complete TPD Registration and Notification in Germany

This stealthy dugout bat looks just like a half-smoked cigarette
If you prefer another way, try using an adhesive remover fluid to fade out the tar and nicotine marks before scrubbing them with your chosen cleaning solution