I see in the recommendations for soldering this module that no-clean paste is suggested. Does this mean this part is unsealed and cannot withstand cleaning?
Wireless Modules are designed for consumers to use it in their application with ease. Hence, to avoid or minimize the cleaning efforts after assembly, datasheet recommends a no clean, type -3 solder paste.
A no-clean solder paste ensures that the residual of solder paste from the assembly reflow does not corrode the copper pad/trace thus, the residual can be left as it is without the need of cleaning it.
If there are any changes in the solder paste type, the user must make sure the 'no clean' specification is maintained. Solder paste types that are not specified as no-clean are assumed to contain solder flux which is corrosive and for which will need to be completely removed from the assembly.
As this is a PCB module, its pads are exposed to the user for cleaning, hence the recommendation to use a no-clean paste is just a recommendation without a strict requirement.
Please let us know if you have any further questions.