I'd sent an email to Can direct asking if I can dry my 5l mini kegs in the oven and here's what they said.
The mini keg without tap is often dried in ovens at about 60°C, which gives a little disinfection too. Afterwards, when they are dried and cold again, you can give a little bit of steropur (250 ml for around 6,00 EUR, is alcohol and water as a spray) into the keg and put the cap on it for storage. Then you can fill it later nearly directly, because the mixture vaporizes after opening and has sterilized the keg before.
Have been quite worried about mine seeing as I've 'drip' dried them and with such a small opening not a great deal actually dries quick enough. Some good tips from them me thinks
