Encourage and discipline your team members to use neat writing when making notes on drawings or things which others must read or refer to.
Messy or illegible writing slows the reader down and leads to miscommunication. It can also lead to mistakes as someone may assume a word is different to what was intended.
The project manager should lead by example.
If you, as the project manager, receive unclear hand written correspondence or drawings with unclear writing, you should return it to the writer and ask them to re submit it to you either typed or written clearly.
This is a communication issue and mistakes could lead to costly delays or safety issues.