Today I had the pleasure of sitting together with a young successful entrepreneur that has at the age of 26 already two offices for his company; one in Prague and one in New York.
We talked about culture and the challenges he is facing in his company with maintaining the culture as the company expanding in two locations, however his greatest concern was how to ensure that all the part-timers and external temporary workers are really in the culture and treating the clients as his full-time employees knows that his  company wants to treat their clients.
After some further explanations from Vojta about his company, I suggested him to try 3 things for his part-timers:
1. Set up an app for them to let the company know when they are able to work (giving the choice to them)
2. Implement a "champion system" where it is clearly communicated how you will celebrate the part-timers success.
3. Set up a 15 min training at the start of each gig of what is your company culture. Make it easy for anyone to train anyone-else on what the core of your company stands for.
After we parted I realized that I had forgotten to tell him the about the:

• "power of t-shirt" - connecting the part-timer to your organisation, so during the first gig give them t-shirts with company logo that is not expected to be used at work. Most people will wear them in their free-time and every time they see the logo in the mirror they will be reminded of your company.
• "power or responsibility" - most companies do not give much responsibility to part-timers, however if you do, they will feel trusted and better connect with your brand.

Connecting part-timers to your organization is always a clever move, as they can be brand ambassadors and sales people of your company, if you are treating them right.
Apart from that it is always the best thing to do - to treat people right and it feels good. It is also very good for your reputation - no negatives only lots of positive outcomes if you invest the time in looking after your part-timers.