Welcome to the Strelets Forum. Please feel free to discuss any aspect of 1/72 scale plastic figures, not simply Strelets. If you have any questions about our products then we will answer them here.
I've used a clear matte acrylic sealant spray sealant (or flat) to seal my paint (test the brand as some leave a type of film - the best I've found is Plaid Patricia Nimmock's for paintings). I've also used the spray on glossy figures to tone them down with some good results.