Anneal.

To the other points I would add,

W/ brass PE, heat till red hot over a gas stove/candle then quickly quenching into water makes the part more pliable/malleable should it need to be formed into curves, shapes.

Tiny parts can be attached w/ clear laq or enamel. Prob water based ones too, tho I don't use them.

I do fine sand or buff w/ a fine Dremel wire wheel most PE parts, if only to remove production residue. Pre-soak in laq thinner for the same reason.

Use solder for some of the bigger PE sub-assemblies (storage boxes, fenders), tho it is a pain, sometimes req'g heat sinks, jigs, holding stands, etc.