Tip: never use silicone anti backing for this it is not possible to remove this. Better are grease types which can be removed in our additional cleaning/degreasing process. Please inform your moulder!
Generally speaking :
For big quantities, more as 5000, metallization is generally the best. For this process which is under vacuum conditions, we need a jig. This tool is to fix the part during the process and eventually can mask the part (to prevent for instance for short circuit). Jigs are designed and built by ourselves in our machine shop has to be produced very accurate and this will take a few weeks to realise this. Bigger sizes as 500 mm make the process of metallization expensive.
When you need parts very quick and the series are small (up to a few hundreds) it is better to use a conductive coating, which can be spayed (by us or yourselves when you are well equipped) or applied with a brush.
When the geometry is easy to cover with a foil or even a textile (so bending in 1 direction) a very good method is to cover the box inside or make a inside box of foil which covers the sensitive parts of the . The tooling is cheap for it is a die cut or laser cut part
When parts are small (up to 100 mm) and there is no need for high mechanical strength, a conductive plastic can be used. Please let your moulder speak with us to find the best compound.
galvanic or chemical treatment
With a is for small parts and big quantities and general speaking when a selective coating is not required.
EMI shielding,EMC,RFI,shielded,shielding,conductive tape,honeycombs,emi gaskets,conductive glue 
