Raised playfield inserts that won't push down: warm them, glue and tap flush
Inserts that have crept up above the playfield (common over hot incandescent bulbs) can be set back down. Warm the area from both sides with a hair dryer, put a little glue or two-part epoxy under the insert lip from below, then tap the insert flush with a wood block and rubber mallet, or press it in a clamp with a soft block. Switching those lamps to LEDs reduces the heat cycling that pushes them up.
Systems
Games
Source: Pinball Repair help group!! (Facebook group)